¹Academician Workstation of Animal Disease Control and Nutrition Immunity in Henan Province, Henan Joint International Research Laboratory of Veterinary Biologics Research and Application, School of Biotechnology and Food Science, Anyang Institute of Technology, Anyang 455000, CHINA DOI : 10.9775/kvfd.2019.23196 Monogenean infection can cause high mortality and significant financial losses in commercially farmed fish. Existing chemical drugs for the treatment of such infections often have serious drawbacks. In order to find alternative agents of chemical drugs, fourteen medicinal plants were tested for their in vivo anthelmintic activity against Gyrodactylus kobayashii in goldfish (Carassius auratus). Ethanol extracts of Evodia rutaecarpa, Cnidium monnieri and Sophora flavescens had 100% anthelmintic efficacy at low concentrations (100, 100 and 300 mg/L, respectively), after 48 h of exposure. The ethyl acetate extract of C. monnieri was the most effective, with an EC50 value of 11.0 mg/L, after 48 h of exposure, showing 100% anthelmintic efficacy against G. kobayashii at 50.0 mg/L. Higher anthelmintic activity was also observed for remaining extracts of C. monnieri and E. rutaecarpa except for the water extracts of the two plants. The ethyl acetate extract of C. monnieri had the highest therapeutic index (TI, LC50/ EC50) value of 31.8, and the lowest EC50, which indicates that this extract was the safest to goldfish among all extracts. For the remaining extracts of C. monnieri and E. rutaecarpa, the 48-h LC50 values were about 10-fold higher than the corresponding EC50 values. This result indicates these extracts have low toxicity in goldfish. The ethyl acetate extract of C. monnieri was the most effective and the safest among the tested extracts. Therefore, the two plants are expected to be alternative agents to control monogenean infection. Keywords : Disease control, Gyrodactylus kobayashii, Chinese Medicinal Herb, Goldfish, Anthelmintic efficacy