Fennel is an herb with yellow flowers. The dried seeds are used in food. The dried seeds and oil are also used as medicine. Fennel is native to the Mediterranean, but is now found throughout the world. As medicine, it might relax the colon, and also appears to contain an ingredient that may act like estrogen in the body. As a spice, fennel has an anise-like taste. People use fennel for menstrual cramps. It is also used for excessive crying in infants, indigestion, and symptoms of menopause, but there is no good scientific evidence to support most of these uses.