Sildenafil 100mg did not work, the first thing to consider is whether there is sexual stimulation after taking the drug; and then consider whether there are other improper use of the drug, if there is, you can adjust the method of use to continue to take the drug to observe; if you exclude the improper use of the drug should be considered to change the drug or change the treatment program. 1. Sildenafil requires sexual stimulation to work after taking the drug, if there is a lack of sexual stimulation after taking the drug, it may lead to the situation that taking 100mg does not work. At this time, appropriate sexual stimulation can be effective. 2. Sildenafil should be taken within 0.5~4 hours before sexual activity, if the time of taking is too short, it may lead to taking 100mg still does not work. At this time, you can adjust the method of use, continue to use the drug several times to observe whether the effect. 3. If the above reasons have been ruled out and still did not work, after ruling out the quality of the drug itself, we should consider the possibility that sildenafil is ineffective for the user. In this case, the patient should be treated with other erectile dysfunction medications (e.g., avanafil) or other erectile dysfunction treatments, such as psychotherapy (e.g., sex counseling) or surgery (e.g., penile prosthesis implantation). It should also be noted that sildenafil is contraindicated in people who are allergic to it or who are using nitrates (e.g., nitroglycerin), guanylate cyclase agonists (e.g., leucovorin), and that dizziness, visual abnormalities, and other adverse effects may be experienced during its use. The use and adjustment of this drug must be carried out strictly under the guidance of a doctor, do not blindly self-medication, in order to avoid adverse consequences.