Nigella sativa (black-caraway, also known as nigella or kalonji), often called black cumin, is an annual flowering plant in the family Ranunculaceae, native to south and southwest Asia.
Nigella sativa grows to 20–30 cm (7.9–11.8 in) tall, with finely divided, linear (but not thread-like) leaves. The flowers are delicate, and usually colored pale blue and white, with five to ten petals.
The black caraway fruit is a large and inflated capsule composed of three to seven united follicles, each containing numerous seeds which are used as spice, sometimes as a replacement for black cumin (Bunium bulbocastanum).
N. sativa has a long history of use as medicine. Modern clinical trials have begun to investigate its efficacy, mainly using the seed oil extract, volatile oil, and isolated constituent thymoquinone. The most trials, and those of the best quality to date, provide preliminary support for its use in asthma (for both prevention and treatment of acute attacks), allergic rhinitis, and atopic dermatitis. Smaller and less rigorous studies suggest it might help people with functional dyspepsia, respiratory problems due to mustard gas poisoning, seizure disorders, diabetes mellitus and the metabolic syndrome, and opioid addiction. One meta-analysis of clinical trials concluded that N. sativa has a short-term benefit on lowering systolic and diastolic blood pressure, and another found that various extracts of black seed can reduce triglyercides, LDL and total cholesterol while raising HDL cholesterol.