Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. NICOTINE, atropine, QUININE, curare, caffeine, CODEINE, COCAINE, MORPHINE, and eserine are all examples of alkaloids. NICOTINE is a stimulant found in tobacco, while atropine is a drug used to treat certain types of heart conditions. QUININE is an antimalarial drug, curare is a muscle relaxant, caffeine is a stimulant found in coffee, CODEINE is an opioid pain reliever, COCAINE is a stimulant and anesthetic, MORPHINE is an opioid pain reliever, and eserine is an alkaloid used to treat glaucoma.