Drinking black coffee usually does not cause delayed menstruation. Drinking black coffee clinically can increase the nervous system mediators, causing sympathetic excitation in the body, which may cause insomnia. Drinking black coffee in large amounts may cause gastrointestinal disorders. Coffee is a stimulant of the nervous system, excessive consumption may tutorial, insomnia if there is a delay in menstruation may be related to pregnancy, clinically more common, may be ovarian dysfunction, mental stress, strain caused by the delay in menstruation. Clinically, if there is a delay in menstruation, occasionally delayed for about seven days is a normal physiological phenomenon and does not require special treatment. If the delay is longer than one week, it is recommended to go to the hospital for appropriate examination.