The study is to primarily investigate whether Treximet® (Imitrex RT/naproxen sodium 500mg) taken at the first onset of menstrual migraine will both terminate the acute headache and assist in preventing headache recurrence and the need for repeat abortive therapy over the ensuing days of menses.

Inclusion Criteria:

1. Actively and regularly cycling females age 19 years or greater.
2. Normal (for subject) menses within 6 weeks prior to randomization
3. History of migraine of ≤ 1 years duration by International Classification of Headache Disorders (ICHD) criteria
4. History of menstrual migraine by ICHD criteria

Exclusion Criteria:

1. Not actively practicing adequate contraception or intending to continue to do so during the treatment.
2. 15 or more days of headache during each of the prior 3 months
3. Prior use of Treximet for the treatment of menstrual migraine
4. Uncontrolled hypertension
5. Hemiplegic or basilar migraine
6. Clinical evidence of coronary artery disease or other clinically significant and relevant cardiac disease (e.g. vasospastic angina)
7. History of stroke or transient ischemic attack
8. History of ischemic bowel disease
9. Clinically significant hepatic disease
10. History of allergy to any NSAID or triptan
11. History of gastritis, peptic ulcer disease, GI bleeding, gastric surgery