Objective: To study the antifungal effect and antifungal mechanism of the essential ethanol extract of Coptidis Rhizoma and Galla Chinensis on Streptococcus agalactiae from viscera of ill tilapia. Method: Low concentration and middle concentration were determined by the agar dilution method(Brain Heart Infusion Broth).Select Galla Chinensis MIC(3.125 g·L-1)

2 time MIC(6.25 g·L-1)

3 time MIC(9.375 g·L-1) for the experiment concentration.Select Coptidis Rhizoma MIC(13.33 g·L-1)

MBC(20.00 g·L-1)

2 time MIC(26.67 g·L-1) for the experiment concentration.The single colony was selected into medium

cultured on the 37 ℃ 200 r·min-1

under the three concentrations

on the 0.5

1.5

2.5

3.5

4.5

5.5

6.5

7.5

8.5 h samples were collected and the quantity of the bacterial colony was counted.Then

time-kill curves observation of the S. agalactiae was carried out. Result: The antifungal effcet of Galla Chinensis low concentration on occuerred from 2.5 h

until 8.5 h.The antifungal effcet of middle concentration and high concentration from 2.5 h

until 6.5 h.The antifungal effcet of Coptidis Rhizoma

middle concentration and high concentration was found at 2.5 h

low concentration at 4.5 h. Conclusion: The Coptidis Rhizoma and Galla Chinensihas powerful antifungal effcet.