10 Common Causes of Headaches

7. Caffeine

Although some people find caffeine can help relieve their headaches, too much can also cause them, not to mention nausea, vomiting, dizziness, weakness, and even abnormal heart rhythms.

The amount of caffeine that causes headaches varies from person to person—some people may be able to tolerate more than others without experiencing side effects. But as a general rule of thumb, 300 milligrams (mg) per day is enough to cause symptoms in some people; this is about 4 cups.

Alternatively, suddenly stopping caffeine can cause withdrawal headaches if you are a regular caffeine drinker, so if you're planning to cut back, you may want to slowly reduce your consumption. Try swapping it out for decaf coffee or tasty teas, which generally have 50% or less caffeine than coffee.