In a continuous search for the improvement of antitumor therapies, the importance of alterations in the Wnt signaling pathway in human tumors was discovered and the idea that its inhibition could improve clinical outcomes and survival of patients was recognized. In the human body, the Wnt signaling pathway is involved in the regulation of embryonic development, as well as tissue and organ regeneration in adulthood. Because the components of the Wnt pathway are often mutated or epigenetically altered in tumors and often contribute to tumor malignancy and invasiveness, new molecules that inhibit this pathway are being intensively investigated. The results of previous studies have shown that blockade of the Wnt pathway by knockdown of its components has an inhibitory effect on tumor growth in vivo and in vitro, so similar effects are expected after the application of Wnt inhibitors. In addition, it is assumed that inhibition of Wnt signaling could stop epithelial-mesenchymal transition cellular process needed for the acquisition of an invasive phenotype. In the last thirty years, molecules that can inhibit Wnt signaling by acting on specific molecular targets in the Wnt pathway have been observed. This review will discuss the inhibitors of the canonical Wnt pathway that have been discovered so far, summarize previous studies on their effectiveness in monotherapy or in combination with other chemotherapeutics and debate on side effects. Primarily the thesis will explain the Wnt signaling pathway and the role of its main components, which are also the site of inhibitor action and the site of frequent mutations in tumors. Some of the molecules identified as Wnt pathway inhibitors have reached earlier stages of clinical trials, however some of these molecules have only just been discovered and have no application in the treatment of human tumors. Furthermore, since the Wnt signaling pathway ensures osteoblast differentiation as well as regeneration of many tissues, especially those with rapid cell turnover, such as the hematopoietic and gastrointestinal systems, inhibition of β-catenin carries certain risks for side effects such as decreased bone strength as well as anemia, neutropenia, thrombocytopenia, nausea, diarrhea and vomiting. Nevertheless, early clinical trials have shown that the severity of these side effects is not significant compared to the potential therapeutic benefits. From this review, it is clear that inhibition of the Wnt signaling pathway has the potential for development of future therapy.