The pattern and intensity of F-18-FDG uptake in the gastrointestinal (GI) tract are variable and can often cause confusion. The purpose of this study was to evaluate the relationship between GI tract symptoms and GI uptake of F-18-FDG. We evaluated whole-body FDG-PET of 314 persons (M:F = 147:167; 13-83 years) in whom pathologic GI tract disorders had not been observed. Uptake score and pattern were evaluated visually. Symptoms were grouped as follows: diarrhea, constipation, and neither diarrhea nor constipation. Among symptom groups, there was no statistically significant difference in FDG uptake score. But intense FDG uptake with focal pattern, which can cause confusion, was observed more frequently in the descending colon of patients with constipation than in those with diarrhea or without GI symptoms. When focal intense FDG uptake is observed in the abdomino-pelvic area, stricter attention to GI symptoms would improve the specificity of whole-body FDG-PET.