Fasciolosis, caused by Fasciola hepatica is a parasitic disease highly prevalent in livestock and humans in the Cajamarca region of Peru. Control of this parasite primarily relies on the use of Triclabendazole (TCBZ). This study aimed to evaluate the efficacy of two TCBZ regimens in human subjects through a therapeutic efficacy test, followed by a controlled efficacy trial in sheep using metacercariae obtained from human cases that failed treatment. For the therapeutic efficacy test, twenty-six patients positive for F. hepatica eggs, diagnosed by rapid sedimentation and Kato-Katz techniques were divided into two groups. Group A (n = 13) received TCBZ for human use (Egaten®) at 10 mg/kg body weight and Group B (n = 13) received 20 mg/kg, both administered orally on two consecutive days. Post-treatment, faecal samples were tested for F. hepatica eggs at 15, 30, and 45 days using the rapid sedimentation and Kato Katz techniques. In the controlled efficacy trial, twelve sheep were orally infected, with 200 metacercariae derived from eggs of subjects not cured after TCBZ treatment. The sheep were randomly assigned to Treatment (n = 6) and Control (n = 6). The Treatment group received a single oral dose of TCBZ (Bilevon®) at 10 mg/kg body weight 106 days post-infection, while the Control group remained untreated. Fifteen days later, all animals were sacrificed, and adult flukes were counted in their livers. Results demonstrated a therapeutic efficacy of 92.31% (95% CI: 63.97-99.81) in Group A and 69.21% (95% CI: 38.57-90.91) in Group B, no differences between the two groups (Fisher's exact, p > 0.05). However, the controlled efficacy trial in sheep showed a negative efficacy value (-37.24%), indicating treatment failure. These findings suggest that TCBZ (Egaten®) at 10 mg/kg is effective against human fasciolosis in Cajamarca; nevertheless, treatment failures appear linked to emerging resistance of F. hepatica to TCBZ in the region.