Orthomolecular medicine is based upon the idea that biochemical abnormalities are responsible for or at least contribute to a majority of illnesses. Instead of searching for a xenobiotic drug that will reverse the symptoms (but not the cause) of a disease, orthomolecular researchers study the body's biochemistry, looking for abnormalities that coincide with the presence of the disease. While it is not always clear whether the abnormal levels cause or are caused by the presiding ailment, there is usually a connection. While it is not always possible to cure a disease completely, often some symptoms can be reversed, generally without side effects. The doctor will often use either vitamin supplements or injections along with chelation therapy to correct these abnormalities. There is generally a certain element of orthomolecular medicine in conventional medicine, as well; most patients is advised to eat a good diet and to get their daily RDA of vitamins and minerals, but orthomolecular medicine goes much further, applying these principles of daily living to major diseases and extending vitamin intake radically past the RDA's paltry amounts. This is known as mega-vitamin therapy and is a large component of orthomolecular medicine. Orthomolecular medicine has been successfully used for many conditions, including atherosclerosis, cancer, schizophrenia and depression. The exact treatment of each varies, of course, but the general principle remains the same. The body is not meant to get sick. Only when something goes wrong will the body become ill. By determining what has gone wrong and reversing it, the body can heal itself without the aid of xenobiotic drugs.