Psyllium, a type of dietary fiber, has been shown to have various health benefits including cholesterol lowering, hypoglycemic, cancer prevention, and laxative effects. However, due to its extremely strong water-holding and gel-forming capacities, incorporation of psyllium into food products on the required amount per serving for health claim is difficult. This study evaluated the effect of acid treatment on water up-taking, swelling, gelling and bile acid binding capacities of psyllium samples. The acid treatments were conducted at different reaction temperatures (25, 37.5, and 50 °C) with different psyllium - solvent ratios (1:2.5, 1:5, 1:7.5, and 1:10 g/mL). The result showed that reaction temperature influenced the effectiveness of acid treatment on physical/chemical properties of psyllium samples significantly, while effects of different psyllium - solvent ratios were not significant. This implicated the acid modification at a high temperature might be a possible method to improve the physical/chemical properties of psyllium for incorporation in food.