AbstractA 24‐year‐old woman was referred to our hospital with joint pain, fever, abdominal pain, and diarrhea. A colonoscopy revealed longitudinal ulcers with a cobblestone appearance throughout the entire colon, suggestive of Crohn's disease. However, treatment with 5‐aminosalicylic acid, azathioprine, and infliximab failed to achieve clinical remission. A colonoscopy 5 months later revealed a diffusely spreading granular mucosa without visible vasculature, compatible with active ulcerative colitis. Based on these serial changes in colonic lesions, we tested the patient for MEFV gene mutations and found variants E148Q and L110P in exon 2. Administration of colchicine resulted in complete clinical remission. Our experience suggests that drastic changes in the features of colonic inflammation may be a clue to the diagnosis of enterocolitis associated with familial Mediterranean fever.