Wild Lettuce Leaf (Lactuca spp.) This ancestor of all lettuce plants was valued as a sedative and pain reliever. Once known as ‘poor man’s opium.’ It is also called 'compass plant' because its leaves turn to follow the sun during the day. Prickly lettuce is bitter to people but horses delight in it. It is used effectively against whooping cough and brings relief to those suffering from bronchitis. It increases urine flow and soothes sore inflamed mucus membrane and chapped skin. The leaves contain sedative properties that act like morphine, only milder. It exhibits a mild sedative effect that relieves pain, insomnia, cramps, urinary tract infections and bronchitis.