no safety issues

This is a phase II randomized, double-blind, placebo-controlled study where eligible subfertile male subjects (age 20 years).

Inclusion Criteria:

1. Male subjects who are 20 years old or older
2. Subjects who are diagnosed as idiopathic oligoasthenospermia
3. Subjects who have a normal baseline hormone profile
4. Subjects who were not able to impregnate female partners in the past 12 months under an active and unprotected sexual life
5. Subject's female partner has no endocrine or genital obstructive disorders and is capable of impregnation.
6. Subjects who have an acceptable baseline liver function
7. Subjects who have a normal baseline renal function.

Exclusion Criteria:

1. Subjects who have been diagnosed as male infertility for more than 5 years.
2. Subjects who have a baseline semen white blood cell count of 1*106/mL.
3. Subjects who have genital/seminal tract obstruction, infection, inflammation or anatomic abnormalities.
4. Subjects whose female partner has been diagnosed as infertility of any kind.
5. Male infertility that is associated with hormonal deficiency/imbalance, poor nutrition, congenital/chromosomal disorders, erectile dysfunction, or psychological disorders.
6. Subjects who plan to undergo artificial insemination of any kind within the study period.
7. Subjects who have been treated with chemotherapy, pelvic irradiation or major pelvic surgery
8. Subjects who will undergo any invasive procedures within the study period
9. Subjects who will undergo any chemotherapy or radiotherapy of any kind during the study period.
10. Subjects who can not or are not willing to undergo the two-week wash-out period for any reasons.