An adsorbent for an oral administration, comprising a surface-modified spherical activated carbon wherein an average particle diameter is 50 to 200 μm, a specific surface area determined by a BET method is 700 m2/g or more, a bulk density is less than 0.54 g/mL, a total amount of acidic groups is 0.30 to 1.20 meq/g, and a total amount of basic groups is 0.20 to 0.9 meq/g is disclosed. The adsorbent for an oral administration has a high adsorbability, and is capable of adsorbing a large amount of toxins during a retention period in an intestine, and of remarkably reducing an amount of urinary proteins excretion.