L-arginine is a natural amino acid that is one of the basic units of protein. L-arginine is a non-essential amino acid, which helps to promote the production of nitric oxide, which is present in blood vessels to induce penile erection. With age, the secretion of L-arginine in the body gradually decreases, and the content of nitric oxide also decreases, so it also leads to the decrease of sexual ability. Appropriate supplementation of L-arginine can help to improve male sexual ability, in addition to hepatic coma patients can also use such drugs, can reduce the level of blood ammonia, can also be used for other causes of high blood pressure appeared in the psychiatric symptoms, note that for the viral hepatitis caused by abnormal levels of aminotransferases can not be used for patients. When using L-arginine, it is recommended to consult a doctor in a regular hospital and take it under the doctor’s guidance.