The object of the present invention is to provide an adsorbent for oral administration capable of adsorbing tryptophan or indoxyl sulfate in large quantities in the presence of a bile acid. The object can be solved by an adsorbent for oral administration, characterized by comprising: a surface-modified spherical activated carbon having a bulk density of 0.30 to 0.46 g/mL, a specific surface area determined by BET method of 1900 m2/g or more, a total amount of acidic groups of 0.30 to 1.20 meq/g, and a total amount of basic groups of 0.20 to 0.9 meq/g.本發明之目的在於提供一種可於膽汁酸之存在下大量地吸附色胺酸或吲哚酚硫酸之經口投予用吸附劑。上述課題可藉由經口投予用吸附劑而解決，該經口投予用吸附劑之特徵在於包含表面改質球狀活性碳，該表面改質球狀活性碳之鬆密度為0.30~0.46g/mL，由BET法所求出之比表面積為1900m2/g以上，總酸性基為0.30meq/g~1.20meq/g，並且總鹼性基為0.20meq/g~0.9meq/g。
