Selenium disulfide lotion is generally not recommended for washing behind acne. Selenium disulfide lotion is composed of octadecanol, alkanolamide, sodium dodecyl sulfate, titanium dioxide, citric acid, lanolin, glycerol, fragrance, purified water in appropriate amount and other ingredients, mainly used for dandruff, prevention and control of seborrhea, seborrheic dermatitis of the scalp, lichen planus, etc. In general, it is not recommended to wash behind the back pimples with selenium disulfide lotion. Some patients may experience adverse reactions such as contact dermatitis, hair discoloration, dry scalp or hair during the use of selenium disulfide lotion. Skin inflammation, vesicles, oozing parts, external genital areas, and those who are allergic to this product are prohibited from using it. It is recommended that patients under the guidance of a doctor, strictly follow the medical advice to use the drug, not blindly use the drug or change the dose of the drug without authorization, so as not to cause adverse effects on the body, triggering the emergence of other diseases.