ABSTRACT The objective of this study was to assess the effect of Suanzaoren decoction on stress response of horses in transportation. A total of six male Ili horses were equally divided into Suanzaoren decoction treatment group (n = 3; basal diet supplemented with Suanzaoren decoction, three times/day) and control group (n = 3; basal diet, three times/day). After feeding for five days, all horses were transported for 8 h to simulate stress. Blood and serum samples were obtained before transport (BT), during transport (T), and after transport (AT). Results showed that there was significant interaction between road transport and dietary Suanzaoren decoction supplementation for the white blood cells (WBC), intermediate cell ratio (MID%), granulocyte ratio (GRAN%), alanine aminotransferase (ALT), glucose (GLU), aspartate transaminase (AST), creatine (CK), cortisol (COR), human growth hormone (HGH), adrenocorticotropic hormone (ACTH) and arginine vasopressin content, insulin (INS), and thyronine 4 (T4) in blood and serum. The highest WBC was found in T group. The highest GRAN%, ALT, GLU, AST, CK, T4, ACTH, and INS contents were observed in serum from AT groups, which was decreased by treatment. In conclusion, dietary Suanzaoren decoction supplementation did relieve horse transportation stress. This study provides a useful clinical therapy for relieving transportation stress of horses. n 3 times/day timesday times day times/day. . days BT, BT , (BT) T, (T) AT. (AT) WBC, (WBC) MID%, MID MID% (MID%) GRAN GRAN% (GRAN%) ALT (ALT) GLU (GLU) AST (AST) CK (CK) COR, COR (COR) HGH, HGH (HGH) ACTH (ACTH content INS, (INS) T4 (T4 groups conclusion (BT (T (AT (WBC (MID% (GRAN% (ALT (GLU (AST (CK (COR (HGH (INS (MID (GRAN