In the preparation of prednisolone tablets, when microfine cellulose(Elcema^(R)) was used as diluents, stability and physical characteristics of prednisolone tablets are as follows; 1. Weight of the plain Elcema^(R) tablets increased by 75% of relative humidity and hardness was weekend, but the temperature (60℃) caused no change of thickness and decreased the weight and hardness. 2. In experimental tableting of prednisolone tablets, the addition of Elcema^(R) caused no difficulty in direct compression method, and the shortening of the disintegration time and increase of the hardness were satisfactory. 3. Dissolution rate test exhibited the result similiar to disintegration test. 4. In the comparison test of Elcema^(R) and Avicel^(R) as adjuvants the physical constants of prednisolone tablets showed nearly a similar tendency.