The study was undertaken to determine the antagonism of the AP1700 on the development of nalbuphine-induced tolerance and physical dependence. AP1700 is an oriental drug preparationcomposed of 5 natural products and is known to have antinarcotic action with an oral dose of 250 mg/kg in rats. AP1700 significantly inhibits the development of antinarcotic action with an oral dose of 250 mg/kg in rats. AP1700 significantly inhibits the development of nalbuphine-induced physical dependence but does not the tolerance. Mitogen-activated protein kinase, which include extracellular signal-regulated kinase (ERK), p38 and c-Jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK) play critical roles in cell growth and survival and drug abuse. The level of pCREB was elevated in the hippocampus by the chronic treatment with nalbuphine, however, the elevation of pCREB was not inhibited by the AP1700 co-treatment. Interestingly, the level of pERK was decreased in the co-treatment with nalbuphine and AP1700 on the cortex and striatum. However, the level of nNOS and NR1 was not modulated by the treatment with nalbuphine or AP1700 on the cortex, hippocampus and striatum in the rat brain. These results suggest that the AP1700 could be used to ameliorate the nalbuphine withdrawal symptoms.