This paper aimed to raise a thin-layer chromatography (TLC) identification method for rhubarb and Phellodendri Amurensis Cortex and inspected skin irritation induced by them. It applied the TLC identification for Rhubarb and Phellodendri Amurensis Cortex in Shuang-bai cataplasm prescription. In this study six rabbits were divided into two groups to observe the skin irritation from Shuang-bai cataplasm on intact and defected skin. Another 36 were randomly divided into 6 groups to observe the acute toxicity from Shuang-bai cataplasm on intact and defected skin. Also 30 guinea pigs were divided into 3 groups to observe skin allergy to Shuang-bai cataplasm. The results showed that the average weight of the group of intact-skin rabbits was 2.026±0.10 kg and 2.427±0.023 kg after medication; the average weight of the group of defected-skin rabbits was 2.170±0.05 kg and 2.540±0.15 kg after medication; Shuang-bai cataplasm produced no irritation on intact or defected rabbit skin, no acute toxicity in rabbits and no allergy on the skin of guinea pigs. The skin allergy rate on guinea pigs of the medication group was 0 at each time quantum. Therefore, it can be concluded that this preparation produces no extreme skin irritation for rabbits, guinea pigs or human beings, and it can be safely put into practice.