Abstract: 1.In order to produce a highly activated colloidal charcoal,the best result was obtained by heating a mixture of 100 parts of sawdust and 150 parts of concentrated sulfuric acid at 150℃ for two hours and subsequently washed with water. 2.The colloidal active charcoal is an excellent adsorbent of methylene blue, caramel,protein hydrolysates,heavy metals,alkaloids and bacterial toxins from solution,but in the adsorption of bacteria it is somewhat inferior than other kinds of charcoal,such as“Norit”,“Fuji-carbbn”,etc. 3.The only defect of colloidal charcoal is that it loses its activity on drying, so that it can only be used in the moist state.It is therefore evident that this kind of active charcoal is not suitable as a commercial product,but,owing to the superiority of adsorptive power,ease of manufacture and availability of raw mate- rials,it is still a valuable decolorising agent for pharmaceutical and chemical manufacture.