In 1875, salicylic acid was introduced as a possible cure for typhoid fever. It was found to be an effective antipyretic In 1899, Aspirin was marketed as an antip yretic without the unpleasant side effects. This indicated that the chemical structures from natural products were changed into better drugs Medicinal Chemistry began• In 1875, salicylic acid was introduced as a possible cure for typhoid fever. It was found to be an effective antipyretic. • In 1899, Aspirin was marketed as an antipyretic without the unpleasant side effects. This indicated that the chemical structures from natural products were changed into better drugs. • Medicinal Chemistry began