Chuquiraga weberbaueri “amaro” (Asteraceae) is a plant species popularly used for the treatment of animal fasciolosis in Peru. However, biological and chemical studies of this species remain scarce. Hence, the objective of the present study was to evaluate the anthelmintic effect of the hydroethanolic and aqueous extracts of C. weberbaueri leaves on Fasciola hepatica, through a controlled and a therapeutic efficacy test in artificially infected sheep. In addition, the chemical composition of the extracts was evaluated using phytochemical screening and analysis by UHPLC-MS/MS. Among the evaluated extracts, the aqueous extract proved to be the most efficient and of low toxicity against F. hepatica, inhibiting about 70% of its oviposition, using a 100 mg/kg dose. The chemical study showed that the major constituents were phenolic derivatives, such as chlorogenic acid and ethyl caffeate,...