OBJECTIVE: This study investigated how polypeptide 2B1 is involved in regulating and governing dampness in rat models with dampness pattern defined in terms ofTraditional Chinese Medicine.METHODS: We randomly divided 48 SPF10-week-old male Sprague-Dawley(SD) rats into a normal group, normal + Aristolochic acid I(AA-I) for5 min group, normal + AA-I for 60 min group,dampness pattern group(DS-Group), dampness pattern + AA-I for 5 min group, and dampness pattern + AA-I for 60 min group. Groups were then treated accordingly. We took out the lung, stomach, liver, spleen, kidney, large intestine, and small intestine tissues to detect gene and protein expression of organic anion transporter polypeptide 2B1(OATP2B1).RESULTS: Gene expression of OATP2B1 in spleen,kidney, and small intestine of rats with dampness pattern was lower than that in normal rats(P