Hydrocodone, also known as dihydrocodeinone, is a semi-synthetic opioid used to treat pain and as a cough suppressant. It is taken by mouth.Hydrocodone belongs to the group of medicines called opioid analgesics (pain medicines). It acts on the central nervous system (CNS) to relieve pain, and stops or prevents cough. When hydrocodone is used for a long time, it may become habit-forming, causing mental or physical dependence.