Best for: Medicine-free relief from minor tension headaches (which, unlike migraines, aren’t debilitating).
How it works: Experts aren’t sure precisely why each therapy is effective, but cold slows blood flow and reduces inflammation, and heat increases blood flow; both of these may ease pain. “Go with your personal preference,” says Jason Rosenberg, M.D., the director of the Johns Hopkins Headache Center at Bayview, in Baltimore. Apply a cold compress (a fabric-wrapped cold pack stays cooler longer) or a heating pad wherever you hurt; limit treatment to 15 minutes at a time.
Keep in mind: You can also alternate the two in five-minute increments. Start with cold, then switch to heat.