Constipation and diarrhea are common during pregnancy, occurring in up to one-third of women. Constipation is often the result of physiologic changes that occur during pregnancy, usually from hormonal effects on gastrointestinal motility. Diarrhea, on the other hand, is often caused by the same disorders responsible for diarrhea in the nonpregnant patient. The incidence, pathophysiology, evaluation, and treatment of constipation and diarrhea during pregnancy are reviewed in this article.