Codeine is used to treat mild to moderate pain and diarrhoea. People usually swallow it in pills.
On its own, codeine is a prescription-only opiate painkiller. It’s used to treat pain that can’t be stopped by more common painkillers. This means you can’t buy it legally without a prescription.
Small amounts of codeine are sometimes mixed with other medicines – like paracetamol, ibuprofen and aspirin – and these can be bought from a chemist or pharmacy.

Because codeine is highly addictive, medicines that contain it (such as co-codamol) carry warnings on the packs about the risk of addiction. They advise that the person taking the medicine doesn’t take it for more than three days at a time without medical advice.
People who take codeine illegally, or abuse their prescription (don’t take it how they should), sometimes crush up the tablets and snort them.