Intake of food products rich in water-soluble fiber,beta-glucan and products enriched with plant stanol esters lower serum cholesterol. Combining 2 functional food ingredients into one food product may achieve additional reductions of serum cholesterol. Our objective was to investigate the effects of a simultaneous intake of beta-glucan plus plantstanol esters on lipid metabolism in mildly hypercholesterolemic volunteers. In a randomized, controlled, 3-period crossover study, 40 mildly hypercholesterolemic men and women received muesli in random order twice a day for 4 wk, which provided, in total, 5 g control fiber from wheat (control muesli), 5 g oat beta-glucan (beta-glucan muesli), or 5 goat beta-glucan plus 1.5 g plant stanols (combination muesli). beta-Glucan muesli decreased serum LDL cholesterol by 5.0% compared with control muesli (P=0.013). Combination muesli reduced LDL cholesterol by 9.6% compared with control muesli (P < 0.001), and by 4.4% compared with beta-glucan muesli (P=0.036). Serum HDL-cholesterol anc triacylglycerol concentrations did not differ after the 3 treatments. Compared with control muesli, beta-glucan muesli increased bile acid synthesis (P=0.043) and decreased cholesterol absorption (P=0.011). Addition of plant stanols did not influence bile acid synthesis but decreased cholesterol absorption (P < 0.001) and raised cholesterol synthesis (P=0.016) compared with control muesli, and the plant stanols decreased cholesterol absorption compared with,beta-glucan muesli (P=0.004). The combination muesli decreased serum concentrations of sitostanol compared with control muesli (P=0.010). Plasma concentrations of lipid-soluble antioxicants did not differ after the 3 treatments. beta-Glucan muesli effectively lowered serum LDL cholesterol concentrations. The addition of plant stanol esters to beta-glucan-enriched muesli further lowered serum LDL cholesterol, although effects were slightly less than predicted.