As a homeopath, he knew the powers not just of ordinary opiates but also of poisons such as aconite, from the root of the plant monkshood; atropine, from belladonna (or deadly nightshade); and rhus toxin from poison ivy. In large doses each could prove fatal, but when administered in tiny amounts, typically in combination with other agents, such compounds could produce a useful palette of physical reactions that mimicked the symptoms of known diseases.