This article is about the drug. For the band, see Codeine (band).

Codeine (INN) or methylmorphine is an opioid used for its analgesic, antitussive and antidiarrheal properties. It is marketed as the salts codeine sulfate and codeine phosphate.

Codeine is an alkaloid found in opium in concentrations ranging from 0.3 to 3.0 percent. While codeine can be extracted from opium, most codeine is synthesized from morphine through the process of O-methylation.