Advantages and disadvantages of drinking coffee The main exciting substance in coffee is caffeine. In addition, it also contains fat and minerals such as magnesium, potassium and copper, as well as vitamin B, aromatics and toxins. In other words, coffee has no nutritional value, but because of the role of caffeine, it has many advantages and disadvantages to the body. 1. The beneficial effects of drinking coffee on the body: on the nervous system: caffeine can excite the brain, eliminate the feeling of laziness, make people feel relaxed and happy, make people concentrate, think quickly and recall the past. Studies have proved that caffeine can speed up people's calculation and computer play, and make car drivers more agile. But there is no scientific evidence that caffeine can improve the quality of work. Cardiovascular: Drinking coffee can speed up the heartbeat, raise blood pressure, promote blood circulation and enhance myocardial contraction. Urinary system: Coffee can dilate renal blood vessels, increase glomerular blood flow, and increase renal water permeability and detoxification function. It can be said that coffee has diuretic effect. For the respiratory system: Caffeine can relax the smooth muscle around the trachea, thus expanding the trachea and increasing the breathing ability. But caffeine can't be used as a drug to treat asthma in clinic. 2. The influence of drinking coffee on the body Disadvantages: Drinking a lot of coffee affects appetite, which may cause vomiting and convulsions, and may also cause gastritis and thick and greasy tongue coating, which will make the body feel tired and weak. Drinking a lot of coffee will increase urine output, damage the bladder and possibly lead to urinary tract infection. Too much caffeine in the body has a negative effect on the nervous system, which can make people insomnia, shaking hands and slurred speech.