Black seed (Nigella sativa) is a flowering plant native to Asia and the Mediterranean. Its seed has been used to make medicine for thousands of years.

Black seed might have effects in the body that help boost the immune system, fight cancer, prevent pregnancy, reduce swelling, and lessen allergic reactions by acting as an antihistamine.

People commonly use black seed for asthma, hay fever, diabetes, high blood pressure, eczema, weight loss, menstrual cramps, and many other conditions, but there is no good scientific evidence to support many of these uses. There is also no good evidence to support using black seed for COVID-19.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for BLACK SEED are as follows:

Possibly effective for…

• Acne. Applying a gel containing black seed extract to the skin might help to improve acne.
• Hay fever. Taking black seed oil by mouth daily might improve allergy symptoms in people with hay fever.
• Asthma. Taking black seed by mouth along with asthma medicines can improve coughing, wheezing, and lung function in some people with asthma. But it seems to work only in people with very low lung function before treatment.
• A lung disease that makes it harder to breathe (chronic obstructive pulmonary disease or COPD). Taking black seed oil by mouth helps to improve lung function in people with COPD who are also using prescribed inhalers.
• Diabetes. Taking black seed powder or black seed oil by mouth daily seems to improve blood sugar levels in people with diabetes.
• A digestive tract infection that can lead to ulcers (Helicobacter pylori or H. pylori). Taking black seed powder along with standard therapies might help to get rid of this infection.
• High blood pressure. Taking black seed powder or black seed oil by mouth might reduce blood pressure by a small amount in healthy adults. But it’s not clear if it helps people with high blood pressure.
• Conditions in a man that prevent him from getting a woman pregnant within a year of trying to conceive (male infertility). Taking black seed oil by mouth increases sperm count and how quickly sperm can move. It’s not clear if it improves pregnancy rates.
• Breast pain (mastalgia). Applying a gel containing black seed oil to the breasts during the menstrual cycle seems to reduce pain.

There is interest in using black seed for a number of other purposes, but there isn’t enough reliable information to say whether it might be helpful.

When taken by mouth: Black seed is commonly consumed in foods. Black seed oil and black seed powder are possibly safe when taken in larger amounts for up to 3 months. There isn’t enough reliable information to know if larger amounts are safe when used for more than 3 months. Black seed can cause allergic rashes in some people. It can also cause stomach upset, vomiting, or constipation.

When applied to the skin: Black seed oil or gel is possibly safe when used short-term. It can cause allergic rashes in some people.

Special precautions & warnings:

Pregnancy: Black seed is commonly consumed in foods. But taking amounts greater than those found in foods while pregnant is likely unsafe. Black seed can slow down or stop the uterus from contracting.

Breast-feeding: There isn’t enough reliable information to know if black seed is safe to use when breast-feeding. Stay on the safe side and avoid use.

Children: Black seed oil is possibly safe for children when taken by mouth short-term and in recommended amounts by weight.

Bleeding disorders: Black seed might slow blood clotting and increase the risk of bleeding. Black seed might make bleeding disorders worse.

Surgery: Black seed might slow blood clotting, reduce blood sugar, and increase sleepiness in some people. This can interfere with drugs used during and after surgical procedures and cause severe side effects. Stop using black seed at least two weeks before a scheduled surgery.

Moderate

Be cautious with this combination.

Amlodipine (Norvasc)

Amlodipine lowers blood pressure. Black seed also lowers blood pressure. Taking black seed with amlodipine might lower blood pressure too much. People taking black seed along with amlodipine should monitor their blood pressure.

Cyclosporine (Neoral, Sandimmune)

Black seed might decrease levels of cyclosporine in the blood. This might reduce how well cyclosporine is able to work.

Medications for diabetes (Antidiabetes drugs)

Black seed might lower blood sugar levels. Taking black seed along with diabetes medications might cause blood sugar to drop too low. Monitor your blood sugar closely.

Medications for high blood pressure (Antihypertensive drugs)

Black seed might lower blood pressure. Taking black seed along with medications that lower blood pressure might cause blood pressure to go too low. Monitor your blood pressure closely.

Medications that decrease the immune system (Immunosuppressants)

Black seed can increase the activity of the immune system. Some medications, such as those used after a transplant, decrease the activity of the immune system. Taking black seed along with these medications might decrease the effects of these medications.

Medications that increase serotonin levels in the brain (Serotonergic Drugs)

Black seed might increase a brain chemical called serotonin. Some medications also have this effect. Taking black seed along with these medications might increase serotonin too much. This might cause serious side effects including heart problems, seizures, and vomiting.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)

Black seed might slow blood clotting. Taking black seed along with medications that also slow blood clotting might increase the risk of bruising and bleeding.

Sedative medications (CNS depressants)

Black seed might cause sleepiness and slowed breathing. Some medications, called sedatives, can also cause sleepiness and slowed breathing. Taking black seed with sedative medications might cause breathing problems and/or too much sleepiness.

Water pills (Diuretic drugs)

Black seed can decrease potassium levels. “Water pills” can also decrease potassium levels. Taking black seed along with “water pills” might make potassium levels drop too low.

Herbs and supplements that might lower blood pressure

Black seed might lower blood pressure. Taking it with other supplements that have the same effect might cause blood pressure to drop too much. Examples of supplements with this effect include andrographis, casein peptides, L-arginine, niacin, and stinging nettle.

Herbs and supplements that might lower blood sugar

Black seed might lower blood sugar. Taking it with other supplements with similar effects might lower blood sugar too much. Examples of supplements with this effect include aloe, bitter melon, cassia cinnamon, chromium, and prickly pear cactus.

Herbs and supplements that might slow blood clotting

Black seed might slow blood clotting and increase the risk of bleeding. Taking it with other supplements with similar effects might increase the risk of bleeding in some people. Examples of supplements with this effect include garlic, ginger, ginkgo, nattokinase, and Panax ginseng.

Herbs and supplements with sedative properties

Black seed might cause sleepiness and slowed breathing. Taking it along with other supplements with similar effects might cause too much sleepiness and/or slowed breathing in some people. Examples of supplements with this effect include hops, kava, L-tryptophan, melatonin, and valerian.

Herbs and supplements with serotonergic properties

Black seed increases a brain chemical called serotonin. Taking it along with other supplements that have this effect might cause serious side effects, including heart problems, seizures, and vomiting. Examples of supplements with this effect include 5-HTP, L-tryptophan, SAMe, and St. John’s wort.

Iron

Black seed might increase the amount of iron the body absorbs. Taking black seed along with iron supplements might increase the effects and side effects of iron.

There are no known interactions with foods.

Black seed oil has most often been used by adults in doses of 1-2.5 grams by mouth daily for 4-12 weeks. Black seed powder has most often been used in doses of 1-2 grams by mouth daily for 8-12 weeks. Speak with a healthcare provider to find out what dose might be best for a specific condition.

Ajenuz, Aranuel, Baraka, Black Caraway, Black Cumin, Black Cumin Seed Oil, Charnuska, Cheveux de Vénus, Cominho Negro, Comino Negro, Cumin Noir, Cyah Dane, Fennel Flower, Fitch, Graine de Nigelle, Graine Noire, Habatul Sauda, Habbatul Baraka, Kalajaji, Kalajira, Kalonji, Ketsah, La Grainer Noire, Love in a Mist, Mugrela, Nielle, Nigella sativa, Nigelle de Crête, Nigelle Cultivée, Nutmeg Flower, Poivrette, Roman-Coriander, Schwarzkummel, Seed of Blessing, Siyah Dane, Shoniz, Small Fennel, Toute Épice, Upakuncika.

To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.

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