A side effect is an effect caused by a drug that is not initially desired in its prescription. Side effects are not necessarily harmful and are generally recognized by their compounds that have been studied at length and have been on the market a long time. They are outlined in the prescription information inside the package. Some side effects can be beneficial or responsible for inconvenient problems: these are called adverse effects. Many side effects are mild, but some side effects can be severe. It is therefore necessary to measure the benefits and risks to assess the utility of the medication in comparison with the adverse effects it can present.