To provide an adsorbent for oral administration which has a high ability to adsorb indoxyl sulfate, indoleacetic acid, and indole, a method capable of easily and advantageously producing the same, and a drug using the same. The adsorbent for oral administration is obtained from spherical active carbon particles formed by carbonizing and activating spherical furfuryl alcohol resin particles obtained by resinifying and curing furfuryl alcohol through a self-condensation reaction.