Xie Aili is the trade name, generic name tadalafil, and sildenafil is mainly used in the treatment of male erectile dysfunction, you need to choose according to the different conditions of the need to take as well as on time to take the method to treat erectile dysfunction. 1. As needed: Sildenafil is generally recommended to be taken 50mg orally about 1 hour before sexual intercourse, and should be taken on an empty stomach. Tadalafil is generally recommended at a dose of 10mg, and tadalafil is not affected by food. 2. Take it on time: Currently, tadalafil is available in small doses of 5mg a capsule, which can be taken on time every day if necessary to maintain the concentration of the drug to treat erectile dysfunction. In addition, sildenafil in the treatment of pulmonary arterial hypertension is also taken every day on time, the specific dosage as well as the time of use of the drug need to be taken according to the doctor’s requirements. Overall, both Sildenafil and Tadalafil are prescription medications and need to be taken under professional medical supervision. Headache, dizziness, vomiting and other discomforts may occur after the use of the drug, and its use is prohibited in people taking nitrate antihypertensive drugs.