Adolescent gynecomastia can be left untreated, but if it is secondary to other diseases such as testicular tumor and cirrhosis of the liver, then it needs to be treated. 1. Adolescent male breast development: it is a physiological phenomenon, due to excessive secretion of sex hormone during puberty, most of them can return to normal within one year, usually no treatment is needed. 2. Testicular tumor: some patients with testicular tumor will secrete chorionic gonadotropin which leads to breast development, the main treatment is to treat the primary disease and testicular tumor, and the main treatment is radical orchiectomy. 3. Cirrhosis: Cirrhosis of the liver will lead to androgen decrease and estrogen increase, due to liver function decreases to estrogen inactivation decreases, then feedback inhibit androgen release. Through the treatment of cirrhosis to solve, can use liver-protecting drugs such as silymarin. Men with mammary gland development should seek medical treatment in time, and decide whether and how to treat the disease after professional examination and diagnosis by doctors to determine the cause of the disease.