The leaves and bark of some trees like the willow contain a substance called salicin. Salicin relieves pain to some extent. People in olden days used to chew the leaves or bark of such trees in order to get relief from pain. In 1853 a French chemist, Charles Frederick von Gerhardt trying to produce salicin or something like it in the laboratory came up with acetylsalicylic acid which is today known as aspirin. Gerhardt tested the substance on a few people and came to the conclusion that chewing bark was better. Subsequently he lost all interest in it. In the 1890s a German chemist, Felix Hofmann trying to find a medicine that would ease the pain of his father's arthritis tried several drugs on him, but without success. He had heard of the synthetic type of salicin produced by Gerhardt. He prepared a batch and tested it on his father. To his astonishment it worked: his father felt the pain receding. Soon aspirin began to be marketed in tablet form. Today it is considered a wonder drug used not only to relieve aches and pains but also to reduce fever and inflammation and the risk of heart attack and to speed the recovery of stroke victims.