We report two studies, in which fibre/placebo tablets were added to a weight reduction regimen in the treatment of moderately obese women. In Study I, 60 females were treated for a two-month period with general dietary advice, providing a mean daily energy intake of 1,400 kcal. In addition, the fibre group received a 5 g dietary fibre supplement. In Study II, 45 females were treated for a three-month period with a similar programme, in which the recommended daily energy intake was 1,600 kcal and the fibre supplement 7 g/day. In both groups weight changes, hunger ratings, blood pressure, defecation pattern and possible side-effects were recorded every second week. Before treatment mean body weight was 95.4 kg (Study I) and 99.3 kg (Study II). Six patients dropped out of Study I, and four out of Study II. In Study I mean weight loss, 7.0 kg, in the fibre group was significantly higher (p less than 0.05) than 6.0 kg in the placebo group. In Study II mean weight loss in the fibre group of 6.2 kg was significantly higher than the 4.1 kg in the placebo group (p less than 0.05). No significant difference in hunger feeling between the groups was found. Systolic blood pressure was reduced in all four groups at the end of the treatment, whereas diastolic blood pressure was reduced only in the fibre group in Study II. The results suggest that dietary fibre is of additive value in the treatment of moderately obese patients. The fibre supplement, however, needs to be comparatively high.