Nigella seeds have little odour, but when ground or chewed they develop a vaguely oregano-like scent. The taste is aromatic and slightly bitter.Nigella have long been used as a medicinal treatment called a cure for "everything except death”. They are often mistakenly called onion seeds because they have a slight onion-like smell. Nigella sativa is an annual flowering plant. It grows to 20–30 cm (7.9–12 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(Nigella Seeds).