Alkaloids are a group of chemicals made from plants and used in medicine and other drugs. Some of the best known of these alkaloids are morphine, opium, quinine, cocaine and nicotine.
Opium is a drug made from a flower, the poppy. Poppies from which opium can be made grow mostly in eastern Asia. Opium and drugs, such as morphine, that are made from opium, are used as pain killers, but they are very dangerous and can be obtained only by a doctor's prescription.
Quinine is a medicine made from the bark of the cinchona tree, which grows in Peru and in parts of southeastern Asia. It is used as a cure for malaria, a fever that attacks people in the southern part of the United States and in the tropical parts of Africa, South America, and Asia. Cocaine is a pain killer made from the leaves of the coca plant in western South America. It is very dangerous, just as are the drugs made from opium. Cocaine was once used by dentists, but novocaine, a substitute for it, is nowused instead. Nicotine is made from the leaves of the tobacco plant.
It is very poisonous, but the amount of nicotine in smoking tobacco is too small to be poisonous. Nicotine is often mixed with water and other liquids and sprayed on plants, to kill insects that destroy crops. There are several cases, besides that of novocaine, in which artificial drugs have been made to replace the ones made from plants. One example is atabrine, which is often used instead of quinine to prevent or control malaria.