Male breast enlargement is also known as gynecomastia. Commonly used drugs include tamoxifen, letrozole, clomiphene and so on. 1. Tamoxifen: Tamoxifen belongs to estrogen receptor antagonist, as estrogen has a promoting effect on breast development, this kind of drug has a resisting effect on estrogen. However, adverse reactions such as loss of appetite and menstrual disorders may occur. It is prohibited for people with fundus disorders, nursing mothers, and pregnant women. 2. Letrozole: Letrozole belongs to aromatase inhibitors, which can induce estrogen levels to decrease and help androgen levels to increase. It is contraindicated in pregnancy, children, and those with severe liver insufficiency. Adverse reactions such as headache, nausea and weight gain may occur after the drug is taken. 3. Clomiphene: It belongs to estrogen receptor antagonist and may cause adverse reactions such as stomach pain, blurred vision, swelling, etc. If the patient has liver function impairment, mental depression and other diseases, it needs to be prohibited. It is recommended that patients with gynecomastia seek medical attention in a timely manner, and the use of drugs should be regulated by the doctor’s instructions in combination with the individual situation.