Codeine Phosphate is a painkiller that is part of a group of medicines called opiates. It's used to treat pain, for example, after an operation or an injury. It's also used for ongoing pain when painkillers such as paracetamol, ibuprofen and aspirin have not worked. Codeine is also used to treat diarrhoea.

It works in the central nervous system and the brain to block pain signals to the rest of the body. It also reduces the anxiety and stress caused by pain.

Codeine phosphate is available on prescription and comes as tablets, a liquid you swallow, a syrup (linctus) and as an injection. Codeine injections are usually only given in hospital.

You can also buy lower-strength codeine from a pharmacy. It comes mixed with paracetamol (co-codamol) or with aspirin (co-codaprin) or with ibuprofen (Nurofen Plus).