Drinking black coffee has the effect of promoting defecation, but it does not have the effect of treating constipation, and black coffee overdose has certain side effects. Constipated people after drinking black coffee, because it contains caffeine and colchicine and other substances, can stimulate the nerves, thereby promoting gastrointestinal peristalsis, in order to achieve the effect of laxative, but it can only achieve the effect of relieving constipation, and can not be from the root of the treatment of constipation. And after excessive consumption of black coffee, may lead to insomnia and endocrine disorders and other phenomena, so black coffee should be consumed in moderation. For the constipation of the crowd, you can eat some crude fiber food, such as bananas, green vegetables, etc., to avoid eating some spicy stimulation of cold food, while moderate exercise, to promote gastrointestinal peristalsis, if constipation is more serious, it is recommended to consult a doctor in a timely manner.