An object of the present invention is to provide spherical activated carbon exhibiting excellent adsorption ability for uremic substances in the body, and particularly for ²-aminoisobutyric acid. Accordingly, provided is an orally administered adsorbent comprising spherical activated carbon containing not less than 0.5 wt% of nitrogen atoms, having a specific surface area determined by the Brunauer-Emmett-Teller (BET) method of 700 m 2 /g to 3000 m 2 , and having an average particle size from 0.01 to 1 mm.