The daily intake of total dietary fibre of a group of 18 healthy volunteers was raised from a mean of 22.1 g to 32 g by supplementing their diet with either 23 g wheat bran or 15 g oats fibre tablets in a cross-over design for two 3-week periods with a wash-out period of 4 weeks in between. Both fibre supplements improved mean glucose tolerance, although not significantly. During the first period, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and very-low-density lipoprotein cholesterol were significantly lowered by both fibre preparations. During the second period significant reductions in TC and LDL-C were obtained only in the group taking the oats fibre tablets. This could probably be explained as an effect of the gel-forming fibre components in oats fibre. High-density lipoprotein cholesterol concentrations remained unchanged. The oats fibre tablet also proved easier to take and caused fewer side-effects. This study shows that if dietary fibre concentrates are used to increase fibre intake in Western societies, better results will probably be obtained by using a dietary fibre concentrate or mixture of concentrates that contain both soluble and insoluble components.