Sweet's syndrome is characterized by tender, red inflammatory nodules or papules, usually affecting the upper limbs, face or neck. It is part of the group of acute neutrophilic dermatoses that includes pyoderma gangrenosum, but can be distinguished by its appearance, distribution and histological features. Four patients with Sweet's syndrome and Crohn's disease are reported. A total of 30 cases from the literature suggest that Sweet's syndrome is an unusual extraintestinal manifestation of either Crohn's disease or ulcerative colitis. There is a strong predilection for women (87%), patients with colonic disease (100%) and those with other extraintestinal features (77%). The rash is associated with active disease in 67-80%, but may precede the onset of intestinal symptoms in 21% and has been reported 3 months after proctocolectomy for ulcerative colitis.