We investigate the potential pharmacokinetic drug-drug interaction between Tadalafil and Tamsulosin in healthy male volunteers who receive Tadalafil alone, Tamsulosin alone, and both together in a 3 period repeatedly.

Inclusion Criteria:

1. Healthy male volunteers, age 20 to 55 years.
2. The result of Body Mass Index(BMI) is not less than 19 kg/m2 , no more than 27 kg/m2
3. Subjects who have ability to comprehend the objectives, contents of study and property of study drug before participating in trial and have willingness to sign of informed consent in writing

Exclusion Criteria:

1. Presence of medical history or a concurrent disease that may interfere with treatment and safety assessment or completion of this clinical study, including clinically significant disorders in kidney, liver, cardiovascular system, respiratory system, endocrine system, or neuropsychiatric system.
2. Liver enzyme (AST, ALT) level exceeds one and a half times more than maximum normal range.
3. Systolic blood pressure <90mmHg or Diastolic blood pressure < 70 mmHg, systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg(Sitting blood pressure) during the screening procedure.