As a doctor to stay up late on duty is a very normal thing, whenever you stay up late will silently brew a cup of coffee, drink a cup or two of coffee refreshing, I think every day coffee is very normal, unless you drink too much, and even instead of water, that will naturally be harmful and unhelpful. Although coffee can be refreshing, but in general, nature is not a healthy drink, if long-term or large amounts of drinking, can bring some adverse effects. Coffee is known as “one of the world’s three major beverages”, has been integrated into our daily life, the main component of coffee is caffeine, caffeine has a strong bitter flavor, but can reduce muscle fatigue, promote the secretion of digestive juices. It has even been found that the caffeine in coffee promotes weight loss. However, the more coffee you drink, the better. Drinking large amounts of coffee not only negatively affects our bodies, but consuming too much caffeine may also lead to poisoning. The dangers of drinking too much coffee every day: 1, too much caffeine intake will make the heart hyperactive, beating rate faster, uneven pulse beat. 2, long-term or large amounts of coffee consumption may lead to cardiovascular disease. 3, too much caffeine in the body will make people insomnia, hand shaking and speech slurred. 4, middle-aged and elderly people drink too much coffee, may cause osteoporosis. 5, people with gastric disease will drink too much coffee to cause gastric disease deterioration. Drinking a lot of coffee will affect your appetite and may cause vomiting and cramps. 6. Drinking excessive amounts of coffee can produce effects similar to those of consuming the same dose of stimulants, which can cause nervousness. If it is the usual habit of drinking coffee every day, once there is no normal caffeine intake will produce headaches, sleepiness, tiredness, resulting in the brain can not work properly, and for people who are not accustomed to drinking coffee, a sudden coffee pour instead may lead to them to appear faster heartbeat, poor concentration and other phenomena. People who like caffeinated beverages or food, the amount of caffeine intake per day is preferably no more than 200 milligrams, due to caffeine there is a difference in individual response, some people may be in the case of a very small amount of intake will cause headaches, rapid heartbeat, etc., it is best to be cautious of drinking, and for pregnant women and young children, coffee should be exempted from it.