FAITH LAPIDUS: The Cleveland Clinic says the cause of cluster headaches is in a brain area known as a trigeminal-autonomic reflex pathway. When the nerve is made active, it starts pain linked to cluster headaches. The nerve starts a process that makes one eye watery and red.

Studies have shown that activation of the trigeminal nerve may come from a part of the brain called the hypothalamus. The Cleveland Clinic says injections of the drug sumatriptan can help. Many other drugs could be used. For example, doctors say breathing oxygen also can help.

Thankfully, modern medicine has ways to treat almost all of our headaches.

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BOB DOUGHTY: This program was written by Jerilyn Watson. June Simms was our producer. I'm ­­­­­­­­­­­­­­­­­Bob Doughty.

FAITH LAPIDUS: And I'm Faith Lapidus. Visit us at voaspecialenglish.com, where you can find transcripts and MP3s of our reports. Join us again next week for more news about science in Special English on the Voice of America.