An adsorbent for oral administration, characterized by comprising a spherical activated carbon, wherein a diameter is 0.01 to 1 mm, a specific surface area determined by Langmuir's adsorption equation is 1000 m2/g or more, and a diffraction intensity ratio, an R value, determined by an equation (1): R=(I15−I35)/(I24−I35)  (1) wherein I15 is a diffraction intensity when a diffraction angle (2θ) of an X-ray diffractometry is 15°, I35 is a diffraction intensity when a diffraction angle (2θ) of an X-ray diffractometry is 35°, and I24 is a diffraction intensity when a diffraction angle (2θ) of an X-ray diffractometry is 24°, is 1.4 or more; and an adsorbent for an oral administration, characterized by comprising a surface-modified spherical activated carbon, wherein a diameter is 0.01 to 1 mm, a specific surface area determined by Langmuir's adsorption equation is 1000 m2/g or more, a total amount of acidic groups is 0.40 to 1.00 meq/g, a total amount of basic groups is 0.40 to 1.10 meq/g, and a diffraction intensity ratio, an R value, determined by equation (1) is 1.4 or more. The adsorbents for oral administration exhibit a useful selective adsorbability, that is, a less adsorbability of useful substances in a body, and a greater adsorbability of toxic substances.