Codeine or 3-methylmorphine (a natural isomer of methylated morphine) is an opiate used for its analgesic, antitussive, antidiarrheal, antihypertensive, antianxiety, sedative and hypnotic properties, to suppress premature labor contractions, myocardial infarction, suppress coughing, as well as many other uses. Codeine is the second-most predominant alkaloid in opium, at up to three percent.