Viagra is the trade name and the generic name is Sildenafil Citrate Tablets, which reaches peak blood concentration around 30 to 120 minutes after administration, and the drug reaches its optimal effect. Sildenafil citrate tablets are mainly used for the treatment of erectile dysfunction in men in clinical practice. The peak blood concentration is reached in about 30 minutes to 120 minutes after taking this product on an empty stomach, so it is recommended to take this product about 1 hour before the start of sexual life, at most once a day. Common adverse reactions to this product include indigestion, flushing, headache, etc. It is clinically contraindicated in people with known allergies to this product as well as in people taking nitrate drugs, children, women, and other groups. It is recommended to consult a physician first and take it as prescribed under the direction of the physician.