A stimulant is a drug that stimulates an organ. Nervous system stimulants range from alcohol (an apparent stimulant only), caffeine, and hallucinogenic drugs, to drugs liable to induce convulsions. Cardiac stimulants include digitalis and adrenaline and are used in cardiac failure and resuscitation respectively. Bowel stimulants have a laxative effect. Uterus (womb) stimulants (oxytocin and ergometrine) are used in obstetrics to induce labor and prevent postpartum hemorrhage.