For a few decades, coffee has known different controversy about its effects on health.
Coffee has a physiological action on human organism, in particular on nervous and circulatory system. Whatever the product, overindulgence damages health and it is true also for coffee.
However, regarding the average of national consumption, which is 2 or 3 coffees a days, this quantity is far from being harmful for health. Caffeine is quickly absorbed by organism. Its action begins 30 minutes after drinking and last only 2 or 3 hours.

Coffee Characteristics

favoured concentration and intellectual performance
good for heart
efficient diuretic
analgesic
favoured digestion
stimulate physical performance