The purpose of this study is to evaluate the efficacy and safety of Laxymig® ER compared with placebo in prophylactic monotherapy treatment of migraine headache.

The purpose of this study is to evaluate the efficacy and safety of Laxymig® ER compared with placebo in prophylactic monotherapy treatment of migraine headache.

Four weeks baseline, following with 12 weeks treatment phase. Subjects migraine are recorded by diary cards and re-evaluated by the investigator.

Subject will have visit every 4-week (+/- 7 days).

Inclusion Criteria:

• Clinical diagnosis of migraine with or without aura (typical aura with migraine headache)
• Subjects who had an average of two or more migraine frequencies per month during the 3 months before screening

Exclusion Criteria:

• Female subjects who are pregnant, lactating
• Chronic daily headache
• Previous treatment with three or more migraine prophylaxis medications failed
• Subjects with hepatic disease whose liver enzymes are over 2 times of upper limit of reference or significant dysfunction
• Coexisting medical, neurological, or psychiatric disorder that may hinder the study according to the investigator's judgment