OBJECTIVE： To investigate the safety of Polyisobutylene （PIB） Gutong plaster by transdermal administration. METHODS： 66 rabbits were randomly divided into a normal group， a group with intact skin and a group with damaged skin. The latter two groups were respectively re-divided into PIB group， the groups of low， medium and high-dose PIB Gutong plaster and Gutong plaster group. An acute toxicity test was conducted on the rabbits， which 14 d of continuous observation was made 24 h after transdermal administration. Another 60 rabbits were divided into several groups as above except for a normal group. A single primary skin irritation test was conducted on them， where skin irritation reactions were recorded 6 h after a single administration based on intra-individual left/right self comparison method. 70 guinea pigs were randomized into a negative control group （vaseline）， a PIB group， a positive control group （2，4-dinitrochlorobenzene）， a Gutong plaster group and the groups of low， medium and high-dose PIB Gutong plaster， which were dosed for sensitization， followed by a skin sensitization test. RESULTS： No obvious toxicity symptoms could be seen after administration of PIB Gutong plaster. The rabbits’ intact or damaged skin had no irritation response to PIB and low and medium-dose PIB Gutong plaster. PIB Gutong plaster caused no irritation response in the rabbits’ intact skin， but slight irritation in damaged skin 1 h after administration. The allergic reaction incidence of the positive control group of guinea pigs was 100％ while that of any other groups was 0. CONCLUSIONS： The PIB Gutong plaster is safe for transdermal administration.