PROBLEM TO BE SOLVED: To provide a manufacturing method of an oral pharmaceutical absorbent good in yield while maintaining absorption performance of a toxic substance of active charcoal, capable of economically manufacturing a pharmaceutical absorbent with suppressing environmental load.SOLUTION: In manufacturing spherical active charcoal having average pore diameter of 1.5 to 3.0 nm, BET specific surface of 700 to 3000 m2/g, average particle diameter of 100 to 1100 μm, surface oxide amount of 0.05 meq/g or more and filling density of 0.4 to 0.8 g/mL, and ignition residue at a measurement according to JIS K 1474-1 (2014) of less than 10%, a flame retardant which vaporizes at less than 1000°C, especially one or a plurality of ammonium chloride, ammonium sulfate, ammonium bromide, tetrabromobisphenol A or guanidine hydrochloride is loaded to purified cellulose or regenerated cellulose which is a raw material, carbonized under nitrogen atmosphere at 300 to 700°C, and steam activate at 750 to 1000°C.SELECTED DRAWING: NoneCOPYRIGHT: (C)2019,JPO&INPIT【課題】経済的かつ環境負荷を抑えた医薬用吸着剤を製造することができ、簡易な工程であっても、活性炭の毒性物質の吸着性能を維持しつつも歩留まりが良い経口投与用医薬用吸着剤の製造方法を提供する。【解決手段】 平均細孔直径を1.5~3.0nm、BET比表面積を700~3000m2/g、平均粒径を100~1100μm、表面酸化物量を0.05meq/g以上及び充填密度を0.4~0.8g/mLであり、JIS K 1474-1(2014)に準拠した測定における強熱残分が10%未満とする球状活性炭の製造に際し、原料である精製セルロース又は再生セルロースに、1000℃未満で気化する難燃剤、特には塩化アンモニウム、硫酸アンモニウム、臭化アンモニウム、テトラブロモビスフェノールA若しくは塩酸グアニジンのいずれか一又は複数を添着させ、窒素雰囲気下300~700℃で炭化し、750~1000℃で水蒸気賦活を行う。【選択図】なし