Berberine is one of alkaloids extracted from Phellodendn Cortex or Coptidis Rhizoma and has extensively used as an antibacterial and antidiarrheal drug. In order to increase the bioavailability of berberine preparation, berberine pamoate was synthesized and investigated on its usage in vitro in vivo. Berberine was more rapidly extracted from herbal plants by hot water extraction method than soxhlet extraction method. Berberine pamoate was easily synthesized from berberine hydrochloride and potassium pamoate solution and identified using the infrared spectrum. Quantitativc analysis of berberine was possible in methanol solution by fluorometric determination. The dissolution rate of berberine pamoate was more decreased than that of berberine hydrochloride in simulated gastric fluid and simulated intestinal fluid. The remaining proportion of berberine pamoate in the small intestine of rat was maintained at high concentration for a long time as compared with that of berberine hydrochloride.