Subcutaneous sumatriptan is an effective treatment for pain from acute migraine headache, and can be used in patients with known migraine syndrome and in patients with primary headaches when secondary causes have been excluded. In limited comparative trials, subcutaneous sumatriptan performed in a manner comparable with oral eletriptan and intravenous metoclopramide, was superior to intravenous aspirin and intramuscular trimethobenzamide-diphenhydramine, and was inferior to intravenous prochlorperazine for pain relief. The most common side effects seen with subcutaneous sumatriptan are injection site reactions and triptan sensations. As with all triptans, there is a risk of rare cardiovascular events with subcutaneous sumatriptan and its use should be limited to those without known cerebrovascular disease and limited in those with known cardiovascular risk factors and unknown disease status. In studies of patient preference and tolerability, the subcutaneous formulation has a faster time of onset and high rate of efficacy when compared with the oral formulation, but the oral formulation appears to be better tolerated. It is important to consider the needs of the patient, their past medical history, and what aspects of migraine treatment are most important to the patient when considering treatment of acute migraine or primary headache. Subcutaneous sumatriptan is a good first-line agent for the treatment of pain from acute migraine headaches and primary headaches.