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.

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.