Viagra, also known as sildenafil citrate, works mainly to improve penile erection in men and is commonly used clinically to treat erectile dysfunction in men. If you have poor erection hardness during sex, consider using this medication about an hour before sex. After use, it can improve the hardness of the penis after erection and improve the quality of sexual life. However, sildenafil citrate also needs to be stimulated in some way after taking it before it works. Taking Sildenafil Citrate for a long time also has some side effects on the body, which may trigger the patient to experience headache, dizziness, vomiting and other symptoms. The drug is forbidden to be combined with nitrate drugs, and it is contraindicated for women, those who are allergic to the product, children, and those whose recent cardiovascular state makes it inadvisable for them to have sex. Patients taking sildenafil citrate tablets should consult a doctor before using the drug, and take it under his guidance, do not take it blindly on your own.