Coffee is a neutral food. Too much acid or alkali will break the balance of the human body and easily bring some diseases. Usually, people pay great attention to acid-base balance in their diet, which can ensure people's health. There are some substances in coffee that can refresh you a little. People will make a cup of coffee when they are sleepy, and then they will feel comfortable and less tired after drinking it, but coffee can't be drunk all the time. Insisting on drinking coffee every day is very harmful to people's health. Occasionally, when you are sleepy at work or study, you can have a drink. If you drink too much, your skin will become dim.