Present study examines the effect of Guar gum (GG) and Modified guar gum (MGG) on the oral bioavailability of a poorly water-soluble drug, Ibuprofen (IBU). Modified guar gum (MGG) was prepared using heat treatment (125-130oC for 2 to 3 hours) method. It was characterized for viscosity, swelling index and water retention capacity. The physical and co-grinding mixtures of IBU with GG and MGG were prepared in 1:9 drug to gum ratio. The physical and co-grinding mixtures were characterized by DSC, FT-IR. The studies confirmed that there was no interaction between drug and carrier. Prepared mixtures were evaluated for solubility study and in vitro dissolution studies. The rank order of solubility was IBUgrounded IBUhysical mixture Co-grinding mixture Co-grinding mixture of IBU and MGG. The bioavailability study of IBU:GG and IBU:MGG mixture were done using male Sprague-Dawley rats. Drug serum concentration was estimated using HPLC method. Cmax value of ibuprofen found in case of IBU:MGG was higher as compared to pure IBU:GG mixtures. About 49 % improvement in oral bioavailability of ibuprofen was resulted with IBU:MGG mixture.