8 Side Effects Of Neem You Should Be Aware Of

It may be hailed as an effective remedy, but there are some things you need to look out for.

Reviewed by Garima Singh, MSc, DNHE, DDHN
Written by Ravi Teja Tadimalla, BSc, Professional Certificate in Food, Nutrition and Health
Edited by Arshiya Syeda, BA (Literature & Psychology), PG Dip
Fact-checked by Sindhu Koganti, BTech (Biotechnology), Certified Health & Nutrition Life Coach  • 

The health benefits of neem in treating various ailments are well-known. But it is important to note the side effects of neem that come with its excessive consumption. Taking 1 to 2 neem leaves per day or 4 ml of neem juice for about 10 weeks seems to be the safe dosage. But exceeding that dose, unless medically advised, can cause adverse effects.

Here, we understand the major side effects of neem and what precautions you can take to prevent them. Keep reading.

protip_icon Know The Flip Side: Neem

Short-Term Effects
May cause stomach irritation and allergic reactions such as inflammation of the mouth

Long-Term Effects
May damage the liver and kidneys and may also lower blood sugar levels.

Drug Interactions
May interact with medications such as immunosuppressants, and diabetes medications.

When To See A Doctor
If you experience vomiting, diarrhea, or drowsiness after consuming neem, then seek medical help.

What Are The Side Effects Of Neem Leaves?

1. May Cause Kidney Damage

Excess neem consumption raises liver issues in women
Image: Shutterstock

A study reports of a case of acute renal failure in an individual after taking a Chinese herbal medicine. The medication, as per the report, contained neem as one of the primary ingredients (1). Though no direct link had been established between neem intake and kidney damage, it is important to be careful. The trend of toxic renal injuries with respect to medicinal herbs is likely to continue (1). Hence, exercise caution.

Some believe that excess intake of neem may also damage the liver. There is no research to support this. But to be on the safe side, if you have liver issues, please consult your doctor before consuming neem.

protip_icon Did You Know?
According to Indian mythology, a few drops of amrita (elixir or ambrosia of immortality) fell on a neem tree when it was being carried to heaven by the Gods. That is how the medicinal properties of neem were believed to have come to be.

2. May Lower Blood Sugar Way Too Much

In a study, a form of traditional medicine made by mixing neem and longevity spinach (a type of spinach found in China) was found to have hypoglycemic properties (2).

Though the hypoglycemic effects of neem seem desirable, if you are on medications for lowering blood sugar, please check with your doctor before ingesting neem (or any other such plant-based medicines).

Doctors recommend small amounts of neem oil for individuals with diabetes as it controls blood sugar levels. But, when taken in excess, the drop may become extreme. Hypoglycemiai  XA condition where your blood glucose levels are way lower than the standard, healthy range, causing confusion, heart palpitations, etc. may cause dizziness and weakness (fatigue) (3).

3. May Lead To Reduced Fertility

Woman suffering from fertility issue for excess neem consumption
Image: Shutterstock

In rat studies, the administration of neem flower extracts blocked ovulation partially. Though neem could be used as an antifertility agent when required, it may also reduce fertility even when not desired (4).

In studies done on rats, mice, rabbits, and guinea pigs, neem was found to reduce male fertility. In male rats, this reduction was as much as 67% in just six weeks. However, neem didn’t seem to stop sperm production (5).

Some experts theorize that farmers use insect repellents made from neem extract on pesticides to hamper their reproductive health so that they do not multiply, resulting in similar effects in individuals who expose themselves to these pesticides. These pesticides are known to disrupt the direction of the sperms and take a toll on the immune system. However, research is lacking in this aspect but there might arise a need for safer Pesticide alternatives.

Olesya Wilson, a certified nutritionist, says, “Neem leaf extract can have a very detrimental effect on male reproduction. Research has linked it to decreases in testosterone and increases in estrogen levels.”

4. May Cause Miscarriage

Excess neem may lead to miscarriage
Image: Shutterstock

In animal studies, neem extracts were found to induce pregnancy. The extracts could terminate a pregnancy with no visible side effects in both rodents and monkeys. Though this could be desirable for someone looking to abort the child, for those who are expecting to conceive, neem intake may not be recommended (6).

While neem may offer immune system support, some theories also state that overexposure to neem may cause the immune system to become hyperactive. This could lead the body to reject the sperm cells and eject them from the conceived embryo. However, there is insufficient information to substantiate this.

5. May Cause Allergic Reactions

Woman looking for stomatitis as neem side effect
Image: Shutterstock

A study discusses a case of allergic contact stomatitis (inflammation of the mouth) after the intake of neem leaves once every week for three consecutive weeks (7).

Though neem is most commonly used for treating allergies and rashes, its excessive use may lead to allergies. We need more research to further understand the other allergies the use of neem may cause.

6. May Lead To Infant Deaths

Studies have shown that neem could be toxic to infants. Doses of neem oil (as small as 5 ml) had resulted in infant deaths (8).

Animal studies also showed the toxicity of neem oil at doses as low as 12 to 24 ml per kilogram of body weight (9).

Though the contaminants in neem oil could be responsible for these effects (and not neem itself), more research is warranted. Neem leaves or their extracts must not be consumed for longer periods. Anecdotal reports state kidney failure in patients who consumed neem leaf teas as a treatment for malaria (10).

The substances in neem are known to cause symptoms of Reye’s syndromei  XA very rare but serious condition occurring in children that causes swelling in the brain and liver. in infants when exposed to neem oil. The consumption of the smallest dosage can be fatal for infants (11).

Insufficient Evidence For The Following

There is less information and research about the following side effects. These have only been validated by anecdotal evidence. However, if you experience any of these side effects after ingesting neem, please stop use and consult your doctor.

7. May Cause Stomach Irritation

Too much neem making her feel stomach irritation
Image: Shutterstock

Excess inhalation or consumption of neem may cause indigestion, stomach irritation, and other digestive health problems. More research is needed to understand how this happens.

8. May Overstimulate Your Immune System

Consumption of neem or neem-based products can boost the immune system. However, heavy doses of neem (especially in patients with ailments) may overstimulate the immune system and cause complications.

Patients who have undergone organ transplants may also need to stay away from neem. The leaves are believed to interact with immunosuppressant medications during surgeries.

However, there is insufficient information in this regard.

protip_icon Trivia
In Sanskrit, neem is known as ‘arista’, which means something perfect, complete, and imperishable.

Infographic: What You Should Consider Before Using Neem

Due to its antibacterial and antioxidant properties, neem is widely used in many home remedies. However, overindulgence may lead to many health issues. So, it is advisable to use it sparingly but with effective dosages.

Several simple methods can help ensure you won’t have a negative experience using this miraculous plant. Check out the infographic below to learn about the preventive measures you can follow to avoid the side effects of neem.

what you should consider before using neem (infographic)

Illustration: StyleCraze Design Team

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Download Infographic in PDF version

The benefits of neem are wide-ranging and wonderful. When taken in the required amounts, it can promote your overall health. However, if you exceed the recommended dosage, it may cause kidney damage, significantly lower blood sugar levels, lead to reduced fertility, trigger allergic reactions, cause miscarriage, overstimulate the immune system, and cause stomach irritation. It can also be toxic to infants. Hence, caution is highly advised when consuming it. However, including 2 to 3 neem leaves or 4 ml of neem juice in your routine helps reap its benefits.

Frequently Asked Questions

Does neem affect hormones?

According to Olesya Wilson, a certified nutritionist, “Neem leaves have been proposed as a male contraceptive. One study found that when taken once a day, neem leaf paste can help with insulin resistance, which is one of the main concerns in women with PCOSi  XA hormonal disorder characterized by enlarged ovaries that results in irregular or a lack of periods during the childbearing years. . It also decreases luteinizing hormone (LH) levels, which are important in sexual development during puberty.”

Does neem affect hair growth?

“Neem oil can be diluted and applied topically to areas like the scalp to stimulate blood flow and hair growth. It has been shown to increase Follicle Stimulating Hormone (FSH) versus control groups,” opines Olesya Wilson, a certified nutritionist. Its antifungal properties may also help fight against dandruff and fungal infection.

Does neem detox the body?

Yes. Neem flushes out toxins from the body and also detoxes the blood (15). It also helps boost liver health by cleansing it and other vital internal organs. From an ayurvedic perspective, neem is considered suitable for skin diseases and the detoxification of blood. (14)

Who should not take neem?

People who had an organ transplant should avoid using neem. It might lower blood sugar levels. However, limited research is available.

Can I take neem on an empty stomach?

Yes. In fact, intake of neem leaves on an empty stomach for a month helps manage and control diabetes (16).

Can neem leaves be eaten raw?

Yes. Neem leaves can be eaten raw, and may keep your gut healthy and safe.

Does neem lower blood pressure?

Yes. The intake of neem has protective effects and can control hypertension (high blood pressure) (17).

Key Takeaways

  • Animal studies have proven that neem has the potential to reduce male fertility.
  • Some studies concluded that neem is toxic to infants.
  • Anecdotal evidence suggests that neem may overstimulate the immune system and cause stomach irritation.

Consuming neem over a long period of time may lead to adverse effects like excessive dryness and itching. Watch the below video to discover its side effects and how you can manage them.


Articles on StyleCraze are backed by verified information from peer-reviewed and academic research papers, reputed organizations, research institutions, and medical associations to ensure accuracy and relevance. Read our editorial policy to learn more.

  1. Acute Renal Failure Induced by Chinese Herbal Medication in Nigeria
  2. Hypoglycemic Effect of Combination of Azadirachta indica A. Juss. and Gynura procumbens (Lour.) Merr. Ethanolic Extracts Standardized by Rutin and Quercetin in Alloxan-induced Hyperglycemic Rats
  3. RSSDI clinical practice recommendations for the management of type 2 diabetes mellitus 2017
  4. Antifertility potential of Neem flower extract on adult female Sprague-Dawley rats
  6. nduced termination of pregnancy by purified extracts of Azadirachta Indica (Neem): mechanisms involved
  7. Allergic contact stomatitis caused by neem leaves (Azadirachta indica)
  8. Neem Oil Poisoning as a Cause of Toxic Encephalopathy in an Infant
  9. Acute toxicity study of the oil from Azadirachta indica seed (neem oil)
  10. Medicinals
  11. Margosa oil poisoning as a cause of Reye’s syndrome
  12. A rare case of toxic optic neuropathy secondary to consumption of neem oil
  13. Therapeutics Role of Azadirachta indica (Neem) and Their Active Constituents in Diseases Prevention and Treatment
  14. Critical review of Ayurvedic Varṇya herbs and their tyrosinase inhibition effect
  15. Neem the Wonder Herb: A Short Review
  16. The Potential Pharmacological and Medicinal Properties of Neem (Azadirachta indica A. Juss) in the Drug Development of Phytomedicine
  17. The protective effect of Azadirachta indica (neem) against metabolic syndrome: A review
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