Codeine is an opioid pain reliever that is available for purchase online. It is used to relieve mild to moderate pain and is often prescribed for short-term use. Codeine can be taken orally in pill form or as a liquid. It is important to take codeine exactly as prescribed by your doctor to ensure the safest and most effective treatment. When buying codeine online, it is important to make sure that the pharmacy is reputable and authentic, as there are many counterfeit products available.