Viagra is the trade name, generic name is sildenafil citrate tablets, can be used to treat erectile dysfunction, is an oral medication, crushed for external use has no effect. Sildenafil citrate tablets can play a role in erecting the penis after entering the blood circulation of the human body, so crushed for external use does not have the role of treating the disease, only oral use of the drug can play a role in the efficacy of the drug. Some patients may experience adverse reactions such as weakness, myalgia, vomiting and angina after taking this product. In addition, sildenafil citrate tablets are contraindicated for those who are allergic to them to avoid allergic symptoms such as shock and skin itching. Sildenafil citrate tablets crushed for external use have no effect, and patients are advised to follow the doctor’s instructions for the correct use of medication, not unauthorized use of medication.