Paracetamol - medicine that relieves fever - The first observations about the analgesic and antipyretic properties of paracetamol were made back in the late nineteenth century when alternative compounds were being sought to reduce fever in the treatment of infections. The antipyretics commonly used at the time consisted of preparations of natural compounds such as cinchona bark, from which quinine is derived, or galenicals based on willow bark, the earliest source of salicylate. Cinchona bark became in short supply and cheaper, synthetic substitutes were needed.