Diarrhea after taking medication constipation, may be caused by too large a dose of medication, usually need to stop using medication and improve through diet. Diarrhea if you take medicine after constipation, mostly because of taking too much antidiarrheal drugs, such as taking too much montelukast, may lead to slow intestinal peristalsis, and there is the role of astringency, which will lead to the formation of constipation of the dry stools, generally need to stop continuing to take antidiarrheal drugs, the symptoms will gradually improve. In addition, after the occurrence of constipation need to drink more water, eat more fresh fruits and vegetables, supplemental water and dietary fiber, generally can improve the symptoms of constipation. Diarrhea medication must be guided by a doctor, the patient can not self-medication, if the medication leads to serious adverse reactions, must be promptly consulted.