This is a prospective multi-center, randomized, double-blind, two treatment period, placebo-controlled study in subjects with migraine headache requiring prophylactic treatment. The patients will be randomized to receive either histamine dihydrochloride sc or placebo (matching vehicle only) sc for 16 weeks. The safety and efficacy outcome measures will be assessed at selected dosing segments during the 16 week treatment phase and 4 weeks (week 20), 8 weeks (week 24) after the last Injection.