Black coffee does not reduce swelling. Usually black coffee contains caffeine, caffeine can somehow play the role of diuretic swelling. However, due to the limited content of caffeine in black coffee, it can not achieve the effect of treatment and prevention of diseases, so it can not play a role in reducing the swelling of the therapeutic effect. There are many reasons for body swelling, usually divided into physiological and pathological factors. Physiological factors are mainly premenstrual edema, or postural edema, usually do not need special treatment. Pathological causes of edema include liver and kidney function damage, cardiac function damage, and certain allergic reactions causing angioneurotic edema. When the body edema, should not blindly rely on black coffee and other foods, but should be timely medical treatment to find the cause, according to the cause of targeted treatment, so as not to miss the condition.