Jennifer Lee, age 8, of Portland, Ore., for her question:

WHAT CAUSES HEADACHES?

A headache is a pressing feeling in the head that is usually a symptom rather than a disease. It can be very mild and go away quickly, or it can be severe and last many days. It has been one of man's most common complaints since ancient times.

Some headaches, that are accompanied by fever, can be the first symptom of serious diseases such as pneumonia. Other headaches can be caused by allergies, constipation or infections. Eating cold ice cream can cause a headache that lasts only a short time. When a person is tired or tense and under physical or mental stress, he can also  develop headaches. Best medicine for this type of problem is sleep, rest and relaxation.

Severe headaches that linger and seem to have no cause should have a doctor's care. Migraine headaches, the type that recur regularly from time to time, usually have to be tolerated.