This work describes the preparation and characterization of different guar gum (GG) hydrogels at different sizes to be used for protein absorption. GG macrogels and micro/nanogels were synthesized through chemical crosslinkingviabulk polymerization and reverse micelle microemulsion techniques, respectively, and high yields, for example, 94 +/- 4% and 91 +/- 6% were obtained. GG micro/nanogels with spherical shape and smooth surface were separated in the range of 1-10 mu m and 300-900 nm by the filtration process. The blood compatibility assay revealed that GG micro/nanogels were blood compatible up to 2 mg/mL concentration with maximum 1.59 +/- 0.97% hemolysis ratio and minimum 84 +/- 2.6% blood clotting index. Furthermore, the cytotoxicity assay demonstrated that linear GG inhibited cell viability at >= 250 mu g/mL concentrations, whereas no significant difference was obtained up to 1000 mu g/mL concentration when compared to the control groups statistically (p > .05). It was further demonstrated that GG micro/nanogels retain great potential to absorb hemoglobin and lysozyme with 59 +/- 7 and 20 +/- 8 mg/g absorption capacity at pH 7.4. Furthermore, the absorption capacity of the negatively charged GG micro/nanogels could be augmented by adjusting the pH conditions down to the isoelectric point (IP) of the proteins.