Objective: To explore the effect of Longdan Xiegan capsules on platelet activation factor (PAF) and endothelin-1 (ET-1) levels in patients with secretory otitis media of liver and gallbladder dampness-heat type. Method: The 60 patients with secretory otitis media of liver and gallbladder dampness-heat type in Foshan Fifth People's Hospital were divided into control group and experimental group according to the random number table method

30 cases in each group. The samples of venous blood were taken before treatment

and middle ear effusion of patients was stored at -80℃ in refrigerator after centrifugation. Patients in control group were treated with the tympanic membrane puncture and cefaclor capsules combined with loratadine tablets by oral administration

while patients in experimental group were treated with the tympanic membrane puncture and Longdan Xiegan capsules by oral administration. After 7 days treatment

the venous blood of patients was collected again

clinical efficacy was evaluated and PAF and ET-1 levels in serum and effusion were determined. Result: The total clinical efficacy of experimental group was better than that of control group (P < 0.05)

with a lower rate of effusion extraction after re-puncturing in experimental group(P < 0.05). There was no significant difference in PAF and ET-1 levels in serum and effusion between control group and experimental group before treatment. The PAF and ET-1 levels in serum and effusion in both groups were significantly reduced after treatment (P < 0.05)

and Longdan Xiegan capsules had a more significant effect than the control group. Conclusion: Longdan Xiegan capsules had significant effect in the treatment of secretory otitis media

and its mechanism may be related to inhibiting the expression levels of PAF and ET-1.