Viagra is the trade name and the generic name of the drug is Sildenafil Citrate, which may cause adverse reactions such as dizziness, headache, visual abnormalities, and nausea in normal people. Sildenafil citrate has vasodilatory effects and is clinically used in the treatment of erectile dysfunction in men. Normal people may also experience adverse reactions associated with the administration of this product, and its common adverse reactions include visual abnormalities, rash, dizziness, headache, dyspepsia, nausea, back pain, myalgia, and so on. Usually, the adverse reactions will disappear on their own in about 24~48 hours after the administration of the drug. It is clinically contraindicated in people known to be allergic to the drug, and the drug should not be used together with nitrate drugs to avoid hypotension. It is recommended to take the drug as required, and normal people should not use the drug indiscriminately.