Erectile dysfunction is disability to achieveÂ or sustain erection to do satisfying intercourse, that occur at lest for three month. Erectile dysfunction patients are significantly increasing every year, especially in male age 40-70 years old. Tadalafil inhibit PDE5 enzyme 10.000 time more potent than PDE1, PDE2, PDE4 and PDE7; 700 time more potent than PDE6; 900 time more potent than PDE8, PDE9, PDE10, and also 14 time more potent than PDE11A1.In elderly erectile dysfunction commonly is caused byÂ aging process, hence in young adult can caused by physiologic factor or stress. Some studies report there is no significant difference of the tadalafilâ€™s pharmacokinetic in young adult and elderly, and in patient with and without diabetes mellitus. The dose of tadalafil does not need to be reguleted in patient who have liver function disturbance, DM, elderly, renal function disturbance, patient who take medicine like erythromycin, ketoconazole, itraconazole, protease inhibitor, and medicine that inhibit the CYP3A4 system. Clinical study report that tadalafil can increase erection significantly and the patient able to do sex intercourse successfully.Tadalafil does not affect the blood pressure or heart rate, neither affect the concentration motility and morphology of the sperm and neither cause eye disturbance. There is no evidence of teratogenicity, embryotoxicity and foetotoxicity in rat that were given tadalafil 1000 mg/kg/day.