To explore optimum usage and dosage of Kaihoujian Spray treating acute pharyngitis and provide references for clinical use. Methods:A total of 12 groups were given Kaihoujian Spray with 4-10 sprays/times，6-10 times/day，then evaluated the best usage and dosage of Kaihoujian Spray on rat acute pharyngitis model induced by 10% ammonia liquor by throat spray and hemolytic streptococcal type B by infection. Results:All the 12 treatments could alleviate the pharyngeal naked-eye and microscopic lesions in rats and the stable dose range was 6-10 sprays/times，8-10 times/day. Conclusion:The best dose range of Kaihoujian Spray in the treatment of acute pharyngitis in rats was 6~10 sprays/times，8~10 times/day.