OBJECTIVE: To improve the preparative method of boric acid ear drops.METHODS: Boric acid ear drops were prepared using ultrasonic wave rather than waterbath heating to accelerate the solution of boric acid,and a comparison was conducted between the ultrasonic method and the waterbath heating method.RESULTS: The prepared boric acid ear drops were colorless supernatant liquid,which met the standard stated by the "Stipulations of clinical preparations in Zhejiang Province" in tests,identification and content.By ultrasonic method,the time spent for preparing boric acid ear drops was shorter(29?4.2) min than by waterbath heating method(18?1.4) min.CONCLUSION: The improved preparative method for boric acid ear drops is simple and feasible and the quality of the preparation is stable and controllable.