Objective: To study the stability of rubrofusarin-6-O-β-gentiobioside of Semen Cassiae. Method: Rubrofusarin-6-O-β-gentiobioside was processed under different temperature

humidity and solvent respectively. The content was determined by HPLC and the remaining percentages of rubrofusarin-6-O-β-gentiobioside were calculated. Result: The stability of rubrofusarin-6-O-β-gentiobioside was influenced mostly by temperature

and secondly by humidity. The stability of rubrofusarin-6-O-β-gentiobioside reduced along with the temperature rising and the humidity increasing; rubrofusarin- 6-O-β-gentiobioside was much more stable in methanol and ethanol than in water and 0.1% hydrochloric acid aqueous solution

and rubrofusarin-6-O-β-gentiobioside transferred to other substance in 0.1% ammonia aqueous solution. Conclusion: Rubrofusarin-6-O-β-gentiobioside should be preserved under low or room temperature in dry condition. Methanol or ethanol should be selected as solvent of rubrofusarin-6-O-β-gentiobioside solution

preserved under low temperature.