The term dietary fibre describes a wide range of highly divergent (mainly polysaccharide) compounds that escape digestion before the colon. Fibre is often regarded as a neutral dietary compound, not interacting with the gut and only offering dietary "benefit" by the consequent absence of calorific macronutrients, or by bulking out luminal content. Although the above benefits are apparent, a number of other physiological effects of dietary fibres in the colon have previously been described. This review outlines these previous observations in terms of the effect of various fibre types on (i) colonic luminal contents (including the resident microflora (ii) the first line of colonic protection, the mucus barrier (iii) the underlying colonic mucosa (iv) the colonic musculature and (v) colonic neurohumoural release, and the subsequent effect on control of gut motility and satiety. This review will further highlight the divergent physiological effects of various fibre types, and their potential health benefits.