Cluster headache is a primary headache syndrome characterized by attacks of severe unilateral headache typically lasting 30 to 180 minutes without treatment and prominent autonomic symptoms on the affected side. Often attacks occur in cycles lasting weeks to months with up to 8 attacks per day, and a minority of individuals continue to experience attacks throughout the year. Persons with cluster headache usually require both acute medication for attacks and preventive treatment to keep the headaches from occurring. Subcutaneous sumatriptan is the most effective medication for acute cluster attacks, but other triptans such as zolmitriptan nasal spray are also effective. inhaling 100% oxygen is also effective and is a useful treatment for those with frequent attacks or contraindications to triptans. Corticosteroids are among the most effective transitional treatments, typically used at the start of a cycle. Dihydroergotamine is an effective treatment for refractory or severe cluster headache with multiple attacks requiring large triptan doses. Verapamil and lithium are among the most effective preventive medications with good evidence of effectiveness, but other studies support the use of gabapentin, topiramate, diavalproex sodium, and methysergide, to name a few. Each of these medications requires monitoring for adverse events and can be discontinued within a few weeks of a cluster headache cycle.