Jennie Eckman, age 13, of Laconia, N.H., for her question:

WHEN WAS CAFFEINE DISCOVERED?

Caffeine is an alkaloid that is found in coffee, tea, cacao and some other plants. It is also present in most cola soft drinks. Caffeine was discovered in coffee in 1820.

Caffeine has a bitter taste and produces pronounced physiological. effects: it increases the blood pressure, stimulates the central nervous system and stimulates the action of the heart and lungs.

The United States Food and Drug Administration does not include caffeine on its ^generallly recognized as safe" list, but acknowledges that no clear evidence of hazard at normal levels of use is found.

Medically, caffeine has been used in treating migraine headaches because it constricts the dilated blood vessels, thereby reducing the pain. It also increases the potency of analgesics such as aspirin.

Caffeine is obtained commercially chiefly as a by product in the manufacture of caffeine free coffee.