PURPOSE: The present study aims to elucidate the efficacy of mahua oil cake extract against argulosis infestation in common carp. METHODS: Aqueous extract of mahua oil cake was prepared using different methods and the best extract was chosen based on its saponin content. Based on the above findings, the in vitro AE (Antiparasitic efficacy) was calculated for Argulus foliaceus. The parasite was exposed to various concentrations of the extract viz., 15, 17, 19, 21, 23 and 25 mg l RESULTS: Under the in vitro test, 100% AE was achieved at 23 and 25 mg l CONCLUSION: Therefore, it can be concluded that the aqueous mahua oil cake extract has a therapeutic effect against the argulosis infection in common carp at a concentration of 16.45 mg l