BACKGROUND: Our aim was to assess the relationship between gastric motor and sensory function and symptom patterns in community subjects and patients with functional dyspepsia (FD) or irritable bowel syndrome (IBS). METHODS: We recruited 291 asymptomatic blood donors, 151 symptomatic blood donors (recurrent abdominal pain or discomfort), and 40 patients with FD or IBS. Abdominal symptoms were assessed using the bowel disease questionnaire (BDQ) and, in addition, the most bothersome symptom complex identified (dysmotility-type, ulcer-type dyspepsia, or IBS). Gastric emptying time (GET (t(1/2), min)) was measured by (13)C-octanoic breath test and a nutrient challenge performed. Twenty randomly selected asymptomatic blood donors, 48 symptomatic blood donors (30 FD, 18 IBS), and 40 patients (23 FD, 17 IBS) had additional function testing. RESULTS: GET (t(1/2)) was significantly (p<0.05) longer in blood donors with FD symptoms (99 (6) min) and FD patients (110 (12) min) compared with asymptomatic controls (76.7 (7) min), but was not significant in IBS blood donors or patients. Overall, 25 of 48 blood donors with symptoms and 18 of 40 patients had slow gastric emptying. GET was most delayed in subjects with predominantly dysmotility-type symptoms (167 (36) min v controls; p<0.01). Symptom intensities after a nutrient challenge were significantly higher in FD patients and symptomatic blood donors compared with asymptomatic controls; 14 of 48 blood donors with symptoms and 16 of 40 patients had a symptom response to the nutrient challenge exceeding the response (mean (2SD)) of healthy asymptomatic controls. CONCLUSION: Gastric emptying and the global symptom response to a standardised nutrient challenge are abnormal in population based (non-health care seeking) subjects with dyspepsia.