Forty organic dyspepsia patients and 40 functional dyspepsia patients, endoscopically diagnosed, were recruited from a gastroenterology outpatient unit and were age- and sex-matched with an equal number of patient controls. A diet history of typical eating patterns for a 7-day period was taken and food portions quantified using a photographic atlas. An interviewer-assisted questionnaire was used to identify present eating habits, dietary patterns reported to exacerbate or relieve symptoms and alterations in eating habits as a result of symptoms. Females with organic or functional dyspepsia reported significantly lower energy intakes (P < 0.01) than controls. Females with organic dyspepsia had significantly lower intakes of fat, carbohydrate, fibre and a wide range of micronutrients compared to controls. Females with functional dyspepsia had significantly lower intakes of fat, sugars and vitamin C (P < 0.05) than controls. Organic dyspepsia patients (male and female) had significantly lower intakes of alcohol and vitamin C than controls (P < 0.05). Patients with organic dyspepsia had higher intakes of milk and lower intakes of fresh fruit and/or fruit juice than controls. The main difference in eating pattern noted was that a significantly lower percentage (P < 0.05) of functional dyspepsia patients than controls regularly ate three meals per day. Large numbers of dyspepsia patients in both groups associated certain eating habits and the consumption of specific foods with exacerbation of dyspeptic symptoms and over 80% of both groups reported food avoidance as a result of this.(ABSTRACT TRUNCATED AT 250 WORDS)