6 Unexpected Side Effects Of Tulsi

The effects of its overindulgence may not be so pretty.

Medically reviewed by Mary-Walker HallMary-Walker Hall, RDN
By Ravi Teja TadimallaRavi Teja Tadimalla, Professional Certificate In Food, Nutrition & Health  • 

Several side effects of tulsi may make you think twice before using it. Tulsi or holy basil has a reputation for being a magical cure-all herb. This is no surprise given the variety of benefits it offers.

Tulsi is widely used in many home remedies. It is so well-known that even today, your elders might advise you to consume it for its health-promoting properties.

You can derive some amazing benefits from tulsi. Ayurveda recommends this herb for its health-boosting benefits. Tulsi, however, also has certain adverse effects you may have to deal with.

It could affect your fertility or affect the effectiveness of certain medications. As a result, you should understand tulsi’s potential side effects.

This article examines the side effects of tulsi, its safety, and any potential drug interactions. Read on.

6 Top Holy Basil Side Effects

Let’s have a look at the unexpected side effects of Tulsi leaves:

1. Eugenol Overdose

Woman having poisining effect from tulsi leaves

Image: Shutterstock


Eugenol is the primary constituent of Tulsi.


It was found that excess consumption of Tulsi can lead to eugenol overdose (1). There is a possibility to consume too much of eugenol that might even lead to poisoning (2).

Eugenol is found in clove cigarettes and some food flavoring.


Bleeding during coughs, rapid breathing and blood in urine.

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You may also experience liver toxicity, nausea, diarrhea, dizziness, or acute kidney injury due to a eugenol overdose (11).

2. Blood Thinning


Tulsi has the property to thin the blood in our bodies. And hence it should not be taken along with other anti-clottingi  XA substance, property, or drug that slows down or prevents the process of clotting in the body. medications (3).


People who already are taking blood-thinning medications like warfarin and heparin should restrict the consumption of Tulsi. Tulsi can intensify the blood thinning properties of the prescribed drugs and lead to more severe complications (4). It is not good for people who suffer from bleeding disorders.


Bruising and/or prolonged periods of bleeding.

3. Hypoglycemia

Woman having low blood sugar level due to side effect of tulsi

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Hypoglycemiai  XA condition when the blood sugar level is below the normal range and causes symptoms like anxiety and heart palpitations. is a condition of abnormally low blood sugar. Though it is not a disease, it can be a sign of health problem (5).


Tulsi is taken by people with high blood sugar to lower their blood sugar levels. But if people who have diabetes or hypoglycemia and are under medication consume Tulsi, it might lead to excessive reduction in blood sugar. This is one of the most dangerous side effects of Tulsi that one should be aware of.


Paleness, dizziness, hunger, weakness, irritability (6).

4. Might Impact Fertility

Excess tulsi consumption leads to infertility issues

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Tulsi might cause infertility in males.


Tests were conducted on male rabbits. The rabbits were divided into test and normal groups. Test group rabbits were two grams of Tulsi leaves for over a period of 30 days. A significant decrease in the sperm count of test group rabbits was noted (7).

5. Reactions In Pregnant Women

Pregnant woman experiencing side effect of excess tulsi consumption

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Excessive consumption of Tulsi by pregnant women may have long term effects both on the mother and the baby. Tulsi might also trigger reactions in pregnant women.


One of the holy basil side effects also include increase in uterine contractions in pregnant women (8). This side effect of Tulsi can lead to complications during childbirth or menstruation.


Backache, cramps, diarrhea and bleeding (9).

6. Drug Interactions

Woman feeling nauseated due to a drug interaction by tulsi

Image: Shutterstock


Tulsi might interfere with the way how our body processes certain drugs.


This is done by using ‘cytochrome P450i  XProteins found in animal and plant tissues that help in the formation of energy and metabolism of drugs. ’ – the liver’s enzyme system. As a result of this, the levels of drugs in the blood might increase or decrease.

Diazepam and scopolamine are two drugs which help reduce nausea, vomiting and nervousness, anxiety respectively. Tulsi might reduce the amnesic effect caused by these two drugs (10).


Heartburn, light-headedness, headache and nausea.

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It is recommended not to chew tulsi leaves because their mercury content and acidic nature can discolor your teeth.

Any substance, however natural it is, has side effects. It might come as a cure for a certain disease. Or it might possess very good healing properties. But that doesn’t make it devoid from side effects.

Infographic: Top 3 Side Effects Of Holy Basil (Tulsi)

Tulsi is used to treat various infections, skin conditions, and other health conditions. But did you realize that it may have several adverse effects as well? Although it has been a staple of Ayurvedic and Chinese medicine for millennia, excessive use can have harmful side effects. See the infographic below to find out more about them.

top 3 side effects of holy basil(tulsi) (infographic)

Illustration: StyleCraze Design Team

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Tulsi is an aromatic herb commonly used in many home remedies for treating a variety of ailments. However, overconsumption can lead to a number of problems. The side effects of tulsi range from affecting fertility to possibly lowering blood sugar levels and liver damage. There is a possibility of eugenol poisoning where your urine and cough may contain blood. In some cases, tulsi may trigger allergic reactions or interfere with the functioning of certain medications, especially blood thinners, diazepam, and scopolamine. If possible, try to limit your intake or stay away from it entirely to avoid such complications.

Frequently Asked Questions

Can tulsi be taken daily?

Yes. It is safe to have 2-3 leaves of tulsi every day. However, excess consumption may prove to be harmful.

Is chewing tulsi harmful?

No. Scientific evidence does not support the claim that chewing tulsi can cause harm.

Key Takeaways

  • Animal studies suggest holy basil may decrease sperm count.
  • Pregnant women should avoid consuming Tulsi as it may lead to uterine contractions.
  • Tulsi can negatively interact with medications like blood thinners and cause severe health damage.
  • People with diabetes should practice caution while using holy basil as it may lower blood sugar levels.
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