Neem, benefit or health problems?

So I have been religiously using neem as a preventative to funggas gnats after I had a very bad infestation. Yes that infestation was caused by poor watering practices and super soil.

But ever since, because it gave me a bit of a scare, I've used neem mixed into my soil as I found it worked very well, and I want to be proactive vs reactive.

I was just watching a live feed on insta, Jotaherb, and they were talking about gnats. I mentioned how I'm using neem, to which Jota replied is an awful product to use. He went on to say because it's a pesticide and attacks the microbes in your soil. As well as there is evidence pointing to it as a cause of an allergy (I cant recall the name, but basically you get violently nauseous and only a hot shower alleviates the symptoms). On top of all that, he went on to say you dont actually know what you're getting in that package and you dont know what was used on the plants that are now in that package.

I plan on reading further into this, but I'm curious your view points on the subject.
Do you use it?
Do you refuse to use it?
Have you noticed negative impacts on your soil, plants or personal health?
Any other information youd like to point out?
Any links on the subject you would like to add?


PS Goolge is telling me it's called cannabinoid hyperemesis syndrome but I believe Jota called it something else...further talking with him...it is hyperemesis.

Douglas will be around shortly

Gnats come from the soil you are using, compounded with over watering. I don't use any pesticides in my grows. I grow indoors, via a HEPA filtered passive intake. I keep my rooms clean and disinfect judiciously after each run with Clorox (tent and equip)

I have seen no convincing evidence neem causes Cannabis hyperemesis syndrome.

I'mback said:

Douglas will be around shortly

Gnats come from the soil you are using, compounded with over watering. I don't use any pesticides in my grows. I grow indoors, via a HEPA filtered passive intake. I keep my rooms clean and disinfect judiciously after each run with Clorox (tent and equip)

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I agree with all that. I wasnt in control when I had the infestation (work away from town for long periods, partner was tending things), and have since dialed in my watering cycle (somewhat as I use blumats so some soil is perpetually moist).

One source of concern is my new worm bin, introducing gnats into the area. I am following all preventative measures to reduce gnats in the bin, but it's still possible and probably likely to get them.

To add to my prevention tactics, I pack perlite into the holes in my pots to prevent moist organic material being exposed giving the gnats a perfect environment.

But this thread is not so much about gnats and prevention, that's just what started me on my neem addiction. This thread is more about using neem specifically and it's possible negative effects on the soil micro biology and personal health.

I also understand about sourcing locally and neem is awful in that regard. But again, this thread isnt about that, just using neem and negative effects. (Not saying you suggested that, just to note to try and keep this thread in the context I've suggested)

GrowingHigher said:

I have seen no convincing evidence neem causes Cannabis hyperemesis syndrome.

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Nothing is pointing at that. The reason is was suggested is because Jota has a friend who was using a large amount of neem and was affected by cannabinoid hyperemesis syndrome. It was noted that this person did not have this issue consuming Jotas flower, and Jota noted that he does not use neem. So they have a theory of their own that the neem was a contributing factor.

They theorize that the systemic build up of neem in the plants is what brought this on to said person

lol some people are allergic to neem

what is so hard to understand this was understood well before prevalent use on cannabis

Neem has been used for over 6000 years in ayruvedic medicine. I have used it to treat lyme's disease and other bacterial/viral infections. I'll eat upwards of 10 grams of ground plant matter some times. In addition to that I will smoke a lot of weed that uses neem as a soil ammendment and a foliar. Never had a problem. No record of people in the ayruvedic tradition ever having health problems related to neem with symptoms of CHS. 99.99999% of people don't seem to think neem causes CHS. Douglas Curtis does. He is wrong. He will try to tell you he isn't wrong and that he has done tests. He will not give you any records. He will just assure you he has been thorough. I believe he is dishonest or has a slight mental illness.

I'mback said:

Douglas will be around shortly

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LOL Indeed.

I personally (and many others I've run across) have issues with neem and azadirachtin in/on my cannabis. It stays in the plant longer than 70+ days, and applications in veg can cause people issues after harvest.

If you're sensitive to azadirchtin/neem, and have a runaway H.Pylori infection, your chances of massive gut and body pain are pretty good. Without an H.Pylori infection, the amount of neem/aza has to be a lot higher for pain.

In low amounts it causes my digestive system to slow, it's actually inflammed and restrictive. Mild nausea, mild flu like symptoms, over all muscle tension.

In large amounts it causes gas bubbles in the intestines, intense clawing pain going from the sides and pulling back toward your kidneys. Intense nausea, spontaneous vomiting, and cyclical vomiting. Ever wanted to scream in pain while you vomit? Yeah... not fun. I once spent about 6 months jumping into a hot bath, each time the hot water heater completed a cycle. Cost me a fortune in water and electricity, and wasn't fun at all.

It's often mistaken for Cannabinoid Hyperemesis Syndrome (CHS), which is a condition some people have to THC itself. I can use all the THC I want, as long as there isn't any aza in it. lol

Douglas.Curtis said:

LOL Indeed.

I personally (and many others I've run across) have issues with neem and azadirachtin in/on my cannabis. It stays in the plant longer than 70+ days, and applications in veg can cause people issues after harvest.

If you're sensitive to azadirchtin/neem, and have a runaway H.Pylori infection, your chances of massive gut and body pain are pretty good. Without an H.Pylori infection, the amount of neem/aza has to be a lot higher for pain.

In low amounts it causes my digestive system to slow, it's actually inflammed and restrictive. Mild nausea, mild flu like symptoms, over all muscle tension.

In large amounts it causes gas bubbles in the intestines, intense clawing pain going from the sides and pulling back toward your kidneys. Intense nausea, spontaneous vomiting, and cyclical vomiting. Ever wanted to scream in pain while you vomit? Yeah... not fun. I once spent about 6 months jumping into a hot bath, each time the hot water heater completed a cycle. Cost me a fortune in water and electricity, and wasn't fun at all.

It's often mistaken for Cannabinoid Hyperemesis Syndrome (CHS), which is a condition some people have to THC itself. I can use all the THC I want, as long as there isn't any aza in it. lol

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That's very interesting DC, and that would be why people are linking the two together. But from my research it seems for the most part, the only symptom in common with neem poisoning is the nausea. But I was reading that hot showers didnt help in the neem cases...whereas, if I'm understanding correctly, hot showers did in fact help you.

Personally I dont have any issues, but that's not to say this isnt something that my body would eventually develope a reaction to. In your case, was it flower you had grown with neem or others products? I ask because I'm curious how long you had used neem, how often it was applied and how long after you began using it did you happen upon these symptoms. I'm curious if it's a build up in your system, a building reaction, or a fairly quick reaction (as in you had symptoms relatively soon after using neem)
From my reading, it seems to be relatively low on the adverse health effects in humans (numbers of cases, not actual effects). But that is based on poisoning and not an allergy. And it seemed temporary in most cases (the ones that didnt result in death. Death is more common in young children and older population), with patients recovering fully with basic support for symptoms.

Health impacts aside, what is your opinion on its effects on the soil microbiology? I've been reading contradicting studies, some saying it is anti microbial, some saying its anti fungal, some saying its anti fungal but relatively harmless to microbes...etc.

I'm not going to start over with my soil (I've put in alot of time and energy to get it to where it is). But I am considering stopping my neem use. Based on how much I've used (1- 1.5kg over time in ~240L of soil), I'm sure this will be in my soil for quite some time..I'm unsure of how long it persists in soil. I'm going to see if I can find papers on that, in the meantime do you have an idea of how long it persists?

Edit: it would seem, in my situation (living soil) based solely on azadirachtin A & B (test was done with commercial product "Margosan-O"), that at 25°C it would take ~19.8 days for A and 20.8 days for B to be at 50% disappearance of the initial concentration. "Two degradation products of azadirachtin were detected, but were not identified."
Further reading is required..

Fitzera said:

That's very interesting DC, and that would be why people are linking the two together. But from my research it seems for the most part, the only symptom in common with neem poisoning is the nausea. But I was reading that hot showers didnt help in the neem cases...whereas, if I'm understanding correctly, hot showers did in fact help you.

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Nausea, vomiting, body pain, and digestive issues are all common symptoms. I personally get constipated when in contact with aza/neem, where most CHS suffers complain of diarrhea.

Most of my baths were to relieve pain in the digestive system, and the clawing pain from my sides toward my kidneys. I had an H.Pylori infection which amplified the pain significantly, and my nervous system already registers an 11, with inputs which should only register around 7.

These days, post H.Pylori removal, I don't get the digestive pain until the dosage is very strong. My baths are to relieve the muscle tension which increases the pain in my skeletal defects and damage areas. I take a hot epsom salt bath every day while using aza-weed.


The one symptom I have not heard from CHS sufferers is hypothermia. A sudden drop in core body temp, unrelated to environment, diet or any other cause except neem/aza cannabis use. It's only happened a half dozen times, but very scary the first few episodes. An under 10 minute period of core body temp so low, you feel you're about to freeze to death.

Fitzera said:

In your case, was it flower you had grown with neem or others products? I ask because I'm curious how long you had used neem, how often it was applied and how long after you began using it did you happen upon these symptoms. I'm curious if it's a build up in your system, a building reaction, or a fairly quick reaction (as in you had symptoms relatively soon after using neem)

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I used cannabis for almost 20 years, then moved to California where 'organic' is king. Neem/azadirachtin products are certified organic, so it's been the go-to insecticide there for decades. I was homeless and unable to grow for almost 2 years. I knew nothing about what was going on, and ended up on mass opiates to help with the pain from the muscle tension and digestive issues.

36 years old and using a walker to get around. Spending 8-10hrs a day chewing opiates and laying flat on my back in the park, since it was the least painful position. (didn't have access to hot baths/showers much when homeless)

When I was able to get back to growing, all the issues went away. I've grown with nearly the exact same ingredients for 15+ years, so it definitely wasn't my method. Strain, terpenes, THC:CBD levels matter not, only aza matters with me.

Moved to Colorado, where legalization had already spread pesticide resistant mites far and wide. So I looked up the best methods known for mite control, and it turned out to be azamax/azatrol or other aza products. BAM! Mite issue gone!

Harvest time, massive issues to the point I was in massive pain in my birth defect and injury areas, massive digestive issues, and oh wow some spontaneous vomiting. You know, where you're talking to someone and you barely have time to turn your head before projectile vomiting? No notification from your stomach or anything it was about to happen. You don't know that one? Yeah, neither had I until this point. Wow.

It wasn't until after that harvest I made the connection. I've personally tested my theory twice since then. Night and day conclusive results, with absolutely zero room for 'misinterpretation.' Cannabis with aza gives me issues, cannabis without aza does not. Strain does not matter, I tested multiple strains with control groups.

Right now I don't have any clean cannabis. I've had issues the last 2 years getting a solid grow down, and finally getting stable. I've been dealing with constipation (Miri-Lax is your friend here) and increased muscle tension from neem/aza donated cannabis. The dispensaries are so polluted I'm unable to take more than a couple tokes a week of it. So bad.

Fitzera said:

From my reading, it seems to be relatively low on the adverse health effects in humans (numbers of cases, not actual effects). But that is based on poisoning and not an allergy. And it seemed temporary in most cases (the ones that didnt result in death. Death is more common in young children and older population), with patients recovering fully with basic support for symptoms.

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What's not studied is neem + cannabis + humans. An amazing number of 'safe things' have been found to be detrimental when combined with people and cannabis. Things which all other studies said were safe.

Fitzera said:

Health impacts aside, what is your opinion on its effects on the soil microbiology? I've been reading contradicting studies, some saying it is anti microbial, some saying its anti fungal, some saying its anti fungal but relatively harmless to microbes...etc.

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Don't know, and no offense, don't care. There are better options than neem for everything, I don't see the point in pursuing neem+cannabis solutions. Yes, I'm aware I have a heavy bias.

Fitzera said:

I'm not going to start over with my soil (I've put in alot of time and energy to get it to where it is). But I am considering stopping my neem use. Based on how much I've used (1- 1.5kg over time in ~240L of soil), I'm sure this will be in my soil for quite some time..I'm unsure of how long it persists in soil. I'm going to see if I can find papers on that, in the meantime do you have an idea of how long it persists?

Edit: it would seem, in my situation (living soil) based solely on azadirachtin A & B (test was done with commercial product "Margosan-O"), that at 25°C it would take ~19.8 days for A and 20.8 days for B to be at 50% disappearance of the initial concentration. "Two degradation products of azadirachtin were detected, but were not identified."
Further reading is required..

Click to expand...

While your living organic soil is not clay based, I would still expect at least a few rotations before it's 'clean' enough to not cause me issues. I've had problems with neem seed meal soils, re-used soils which used neem seed meal and/or neem and aza products. The soil around here is heavily clay based, which holds it for years. The heavy clay soils have tested positive for glyphosate after 20 years of no application. Nice, yeah?

Cannabis is awesome at pulling things out of the soil. It's why it's extremely useful for cleaning toxic soils through phytoremediation.

I used drip through coco and perlite hempys for my tests, and the plants were still heavily tainted at 70+ days of flower. Plants sprayed with a 3-5ml solution of azatrol or azamax (tested with both) were still tainted at harvest time. Tested both 2 weeks before flowering and day of flip, as well as root drench 2 weeks before flower. All treated plants gave me significant issues, while the exact same clones (untreated control groups) were absolutely wonderful.

This was 10 years ago and all the dispensaries are still using neem/aza. *facepalm* Still waiting on 'the industry' to replicate my tests, so they can see what's really going on. (Edit: and I remember reading recently where dispensary workers are being threatened with lawsuits for talking about neem/aza/CHS with customers?)

I see two possible vectors which could be causing the problem.

1. Something people are coming in contact with which is destroying a bacteria they need to break down aza. (cause of peanut and other allergies)
2. The cannabis plant breaks down aza to compounds no other plant (known) does, and humans/animals have issues with these compounds.


Appreciate the calm discussion, this is a very emotional topic for a lot of growers.

Douglas.Curtis said:

Nausea, vomiting, body pain, and digestive issues are all common symptoms. I personally get constipated when in contact with aza/neem, where most CHS suffers complain of diarrhea.

My apologies, I wasn't aware there was so much cross over of symptoms. I'm still reading more.


The one symptom I have not heard from CHS sufferers is hypothermia. A sudden drop in core body temp, unrelated to environment, diet or any other cause except neem/aza cannabis use. It's only happened a half dozen times, but very scary the first few episodes. An under 10 minute period of core body temp so low, you feel you're about to freeze to death.

That is bizarre, I wonder if the body is going into shock and pulling blood to the vital organs in this case.

What's not studied is neem + cannabis + humans. An amazing number of 'safe things' have been found to be detrimental when combined with people and cannabis. Things which all other studies said were safe.

That's interesting and a very good point. Probabition has screwed us very well. In this day and age we should know so much more about this plant and these compounds than we currently do.

Don't know, and no offense, don't care. There are better options than neem for everything, I don't see the point in pursuing neem+cannabis solutions. Yes, I'm aware I have a heavy bias.

Absolutely no offense taken, I respect your opinion.

I see two possible vectors which could be causing the problem.

1. Something people are coming in contact with which is destroying a bacteria they need to break down aza. (cause of peanut and other allergies)
2. The cannabis plant breaks down aza to compounds no other plant (known) does, and humans/animals have issues with these compounds.

Based on the one study I read earlier, I lean towards option 2 due to the acknowledgement that aza was broken down but what it was broken down to was not identified. It could be something like designer drugs where a tiny modification is made to the molecular structure which in turn creates something similar in structure but completely different in action.

Appreciate the calm discussion, this is a very emotional topic for a lot of growers.

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I truly appreciate your response, your honesty and your time. This is exactly what I was aiming for with this thread. I'm here to learn.

I've exposed myself to a myriad of chemicals and compounds over the years due to stupidity, experimentation and industrial work...I need to really start looking at what I'm doing and how it can affect my health now and in the future. And I cannot be content if I cause someone else issues with my flowers.

My pleasure.

Without the H.Pylori infection, I doubt I ever would have connected aza with the issue. I would have to ingest quite a lot of neem/aza now to reach that level of discomfort.

Most people with low level symptoms simply attribute it to something they ate. As the level of aza/neem waxes and wanes, so do their pains and digestive symptoms. You can literally have progressively worsening digestive issues over a long period, which doctors will never associate with neem/aza.

When your offal starts smelling like a commercial kitchen drain, that rotten food smell, you're pretty bad off. When your burps start smelling the same way, you really need to get your digestion going again.

Douglas, how come I, personally, have been able to consume 15+ grams of powdered neem daily for 60+ days straight with none of these symptoms, all the while consuming high amounts of cannabis that has been treated with neem?

So we’re obviously talking concentrated neem oil products? I saw one person mention neem meal in the soil. That’s the first negative benefit of heard to it in the soil.

Has anyone just tried the recommended dilution of 4 tablespoons per gallon of Dr. Broners soap for a plant spray for bugs? It’s what I do and I’ve never had a problem. with pests. I use the unscented soap and apply it with a paint sprayer that helps coat the underside of the leaves. I think a paint sprayer atomizes the solution. You can play with adding cayenne, tea tree or camphor oil. But I’ve never found it necessary. The soap not only kills them but washes them away.

Even indoor plants in air filtered rooms will accumulate dust over the coarse of a grow. Especially when growing long flowering sativas like me. A friend in Cali recently turned me on to the practice of washing your buds. Said you’d be surprised how much dirt is left in wash water when rinsing a harvest. I imagine Dr. B’s recommended dilution of 1-2 tsp per gal for a vegetable rinse would work well for this practice. And as far as residue, anyone who’s used Dr. B’s can attest to how quickly and cleanly it rinses away with fresh water. An alternative to this is bathing and rinsing the plants prior to harvest while still standing. Decrease humidity and increase airflow appropriately to dry them out then cut and hang like normal. I’m gonna try it this year. Only thing I will clarify is to be sure that the concentrations of soap we are talking will not dissolve the oily trichomes. I think i recall that trichomes are encased in a clear waxy shell. I have used Dr. B spray at much higher concentrations than recommended here and have not had damage to trichomes. But it’s good to be sure and exact in the recipe.

I use it in the soil, would never use it on foliage. And I am very picky about clean contaminant free vapor,and very sensitive to stomach issues.

Cannabis hypermesis comes from any and all horticultural oils sprayed on the plant. Once you fuck yourself over by smoking oil-sprayed plants repeatedly your body demotes your brain and gives a physical response to any vaguely associated signal it receives.

For example: When I was young and wreckless I was injecting ketamine regularly for some time before my body demoted by brain and developed an intolerance to the manmade chemical. Months after I stopped use, I was submitting blood at the Std clinic and my body KNEW I was shooting up ketamine and gave the negative response to ketamine although none was presented. My brain was still on probation and was charged with a perceived violation. The body doesn't get nearly this credit it deserves for protecting us!

BullDogDad said:

So we’re obviously talking concentrated neem oil products? I saw one person mention neem meal in the soil. That’s the first negative benefit of heard to it in the soil.

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No, straight neem oil (not clarified) has between 200-2000ppm/oz of azadirachtin in it naturally. This causes the same issue because, well... it's azadirachtin.

Neem seed meal will also cause issues when the plant comes in contact with enough of it. It doesn't break down in soil very quickly, so products which are applied to the same soil season after season will continue to increase the concentration. I've had plenty of cannabis from growers who only used neem oil or neem seed meal in the soil. No thank you.

Douglas I just don't see how this is possible when people consume tens of grams for months on end for medical purposes. I personally have used 10-12 grams of neem a day to treat lyme's with no adverse side effects. I kept this up for 3 months. It was the powdered leaf, but I've also used the bark.

Covered this topic at the end of my interview with Dr. Adie Rae on the Cannabis Cultivation and Science Podcast. She's a neurologist and she shared her thoughts. Hope that helps.

Here is a direct link to the podcast from the interview between Kisorganics and neuroscientist Dr. Adie Rae.
https://www.kisorganics.com/pages/cannabis-cultivation-and-science-podcast-episode-58

The Neem VS CHS topic starts around minute 52 in the interview.

@KIS, thank you for having come here and share your podcast with us. As always all your content is great and I have been a fan of you guys for years.

KIS said:

Covered this topic at the end of my interview with Dr. Adie Rae on the Cannabis Cultivation and Science Podcast. She's a neurologist and she shared her thoughts. Hope that helps.

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Dr. Adie Rae's research is from medical ER reports? I can see why her conclusion is very wrong for those sensitive to azadirachtin.

No offense, but I've dealt with this for over 10 years. I took the time to test my theory and (for me specifically) it is DEFINITELY the azadirachtin. As far as I'm aware (and I've been to the ER for this several times in the last 10+ years) doctors and patients are nearly 100% clueless on properly identifying tainted cannabis.

I use concentrates all the time, I smoke cannabis all day while I'm awake. The same clone I can smoke all day without azadirachtin, causes me hyperemesis issues when it's tainted with neem, neem seed meal or azadirachtin.

Definitely NOT a THC related thing for me, and never has been in my entire 30+ years of cannabis use. After 7+ years of attempting to expand grower/smoker awareness of this issue, I really don't appreciate negative comments about the azadirachtin problem as a wild viral story. Especially when the research is cursory from 2nd hand reports.