Several commercial beers have been analyzed for their content of β-glucans, pentosans and their degradation products using high performance liquid chromatography, thin layer chromatography and chemical and enzymic analysis procedures. The beers tested contained high levels of residual high molecular weight pentosan, but much less high molecular weight β-glucan. The beers also contained sizeable levels of oligosaccharides, especially trisaccharides, reflecting the incomplete degradation of polymeric materials in malting and mashing and the inability of yeast to ferment them. There is substantially more β-linked glucosyl material in beer than pentosyl substances, although the higher molecular weight of the latter probably makes it more likely to represent soluble fibre. In respect of fibre claims for the beers examined, even for the beer containing the least pentosan, it seems that less than a litre of the product would afford sufficient material.