AIM: To study the suppressive effect of c hu ankezhi (CKZ) injection, a Chinese medicine, on murine allergic contact dermatit is (type IV hypersensitivity). METHODS: Mice were divided into 6 groups according to different medicine treatments: CKZ high, middle, low dose ( CKZⅠ,Ⅱ,Ⅲ) groups, dexamethasone(DEX), benadryl and saline groups. Murine alle rgic contact dermatitis was induced by intraperitoneal injection of 2, 4-dinitro fluorobenzene. Different medicines were administrated at 2 h before sensitizatio n on day 0 and day 1, day 2, 2 h before elicitation and 6 h after on day 5. The six experimental groups were compared according to left ear thickness difference (S1), left ear weight difference (S2), body weight difference (S3) and dermal i nflammatory infiltration cell number. RESULTS: Compared with saline group, the left ear swelling and d ermal inflammatory infiltration cell number were significantly reduced in CKZⅠ, Ⅱ,Ⅲ and DEX groups (P