Why should a plant product affect the human nervous system ?
Is it just an accident? Probably. Plants are great chemists, making hundreds of thousands of different compounds, some of which happen to affect us. How was it discovered? We do not know. People are acute observers of animals and may have noticed unusual effects of plants on animals, and then tried the plants themselves. Opium has the same effect on some animals as it does on people, depressing the central nervous system. The Western Opium experience–Raw opium gum has a long history of medical uses. In Europe capsules with opium have been found over 4000 years old in Switzerland ; Sumerians wrote that opium relieved pain 4500 years ago, and Hippocrates recommended opium for medical problems. All of this early experience was with the raw gum. Morphine was isolated in 1805, and replaced crude opium. Another common opium alkaloid is codeine, which was isolated a short while later. Codeine has a long history as a cough suppressant. Both morphine and codeine are strongly addictive, and man
