The thirty subjects were randomly divided into 2 groups, the 12 subjects in the Yang MP group treated by needling at Hegu (LI4), Quchi (LI11), Zusanli (St36) and Shangjuxu (St37), the 18 subjects in the Yin MP group treated by needling at Neiguan (Pc6), Chize (Lu5), Sanyinjiao (Sp6) and Yinlingquan (Sp9). All the needling was conducted at one side of body.