Worldwide, 6.7 million metric tons of coffee were produced annually in 1998–2000, and the forecast is a rise  to 7 million metric tons annually by 2010. Scientific studies have examined the relationship between coffee consumption and an array of medical conditions. Most studies are contradictory as to whether coffee has any specific health benefits, and results are similarly conflicting regarding negative effects of coffee consumption.

Coffee appears to reduce the risk of Alzheimer's disease, Parkinson's disease, heart disease, diabetes mellitus type 2, cirrhosis of the liver and gout. Some health effects are due to the caffeine content of coffee, as the benefits are only observed in those who drink caffeinated coffee, while others appear to be due to other components. For example, the antioxidants in coffee prevent free radicals from causing cell damage, increasing life expectancy.

Coffee's negative health effects are mostly due to its caffeine content. Research suggests that drinking caffeinated coffee can cause a temporary increase in the stiffening of arterial walls. Excess coffee consumption may lead to a magnesium deficiency or hypomagnesaemia, and may be a risk factor for coronary heart disease. Some studies suggest that it may have a mixed effect on short-term memory, by improving it when the information to be recalled is related to the current train of thought, but making it more difficult to recall unrelated information. Nevertheless, the mainstream view of medical experts is that drinking three 8-ounce (236 ml) cups of coffee per day (considered average or moderate consumption) do not have significant health risks for adults. An American scientist Yaser Dorri has recently suggested that coffee beans can restore the appetite after cooking and refresh olfactory receptors. He believes the intense odorants in coffee release the sensory receptors in the nose. This scientist suggest that people can regain their appetite by smelling coffee beans.