An object of the present invention is to provide spherical activated carbonexhibitingexcellent adsorption ability for uremic substances in the body, andparticularly for.beta.-aminoisobutyric acid. Accordingly, provided is an orally administeredadsorbentcomprising spherical activated carbon containing not less than 0.5 wt% ofnitrogen atoms,having a specific surface area determined by the Brunauer-Emmett-Teller (BET)method of700 m2/g to 3000 m2, and having an average particle size from 0.01 to 1 mm.