Nigella sativa (black caraway, also known as black cumin, nigella or kalonji) is an annual flowering plant in the family Ranunculaceae, native to eastern Europe (Bulgaria, Cyprus and Romania) and western Asia (Turkey, Iran and Iraq), but naturalized over a much wider area, including parts of Europe, northern Africa and east to Myanmar.this plant 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 coloured pale blue and white, with five to ten petals. The 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). Nigella seed contains a lot of thymoquinone. Thymoquinone is the active ingredient in Nigella and is a powerful antioxidant. Studies show that it lowers blood sugar, blood pressure and cholesterol.India, Pakistan, Syria, Turkey, Saudi Arabia, Egypt and Bangladesh are the main producers of quality Nigella .