The adsorption of erythrosine in the aliphatic alcohols by antibiotics such as ampicillin anhydrous, ampicillin trihydrate, amoxicillin trihydrate, cephalexin monohydrate was studied. The adsorption isotherms were all described with Freudlich equation. From the various experimerts, it was found that the adsorption of erythrosine by antibiotics in the aliphatic alcohols was affected by the solubility of adsorbents. The adsoption in the mixture of aliphatic alcohols and water is related with the dielectric constant of mixed solvents. According to increase in the pH values of aqueous solution, the adsorption of erythrosine for antibiotics is decreased, but increased in the mixture of aliphatic alcohols and water. The adsorption of erythrosine in the suspension of antibiotics showed a correlation with the temperature. Colloidal silica which is used as stabilizer had a favorable effect on the adsorption of erythrosine in the suspension of antibiotics.