INTRODUCTION AND OBJETIVE: Colorectal cancer is the third most common cause of cancer-related deaths in the world. Hyperactivation of the Wnt/β-catenin pathway occurs in about 95% of cases, and changes in the components of this pathway are related to initiation, increased aggressiveness as well as the chemoresistance to conventional therapies. In this context, the use of molecules capable of inhibiting this pathway, such as the chalcones loncocarpin and derricin, has been considered to be promising approaches for new anticancer therapies. Thus, the present work aims to evaluate whether lonchocarpin and derricin chalcones are capable of sensitizing the tumor by inhibiting the Wnt pathway and potentiating the effects of chemotherapy 5-fluorouracil (5-FU). MATERIAL AND METHODS: In this study, we used colorectal cancer cell lines with different degrees of malignancy and status for the Wnt pathway, the wild-type RKO cell (carcinoma) in addition to the SW480 (adenocarcinoma Dukes B) and DLD-1 (adenocarcinoma Dukes C) cells, which harbor APC mutation, making the pathway constitutively active. First, we treated the cells for 48 hours with different concentrations of 5-FU, lonchocarpin, and derricin, both individually or combined. Then, the cells were submitted to various experiments to check the Wnt activity as well as cell proliferation, growth, viability, and death. RESULTS AND CONCLUSION: We observed that 5-FU, lonchocarpin, and derricin inhibits Wnt/β-catenin signaling in a dose-dependent manner in the Wnt-specific reporter assay. The combination of 5-FU with both lonchocarpin and derricin did not change the viability of SW480 e DLD-1 in comparison to 5-FU alone after 48 hours of treatment in the MTT assay. However, the combination of 5-FU with lonchocarpin and derricin was more efficient for the inhibition of cell proliferation and growth than 5-FU alone in the clonogenic assay. Thus, these data support the hypothesis that Wnt/β-catenin inhibition enhances the effects of the chemotherapeutic 5-FU and can improve the efficiency of anticancer therapies in Wnt-dependent tumors.