Baiyunshan Jingo is the trade name for the generic name sildenafil, and the effectiveness of one 25mg capsule lasts about 4 hours. Sildenafil belongs to the PDE5 inhibitor class of drugs, mainly used in the treatment of male erectile dysfunction, can effectively improve erectile hardness. It takes effect about half an hour after taking it, and the patient will have a full erection within 4 hours after being sexually stimulated, but it does not mean that the patient can continue to have sex for 4 hours after taking it. Sildenafil belongs to the category of prescription drugs and should not be purchased and taken blindly, adverse reactions may occur, such as dizziness, headache, flushing, blurred vision and so on. This drug is contraindicated in women, people who are allergic to the product, children, and people whose recent cardiovascular state makes sexual intercourse inadvisable. In addition sildenafil can not be combined with nitrates, which may be life-threatening. It is recommended that patients, if needed, consult a doctor in a timely manner, do not be negligent, so as not to affect your health, the drug must be used under the guidance of a doctor.