 Mesenchymal stem cells, MSCs, are adult stem cells that have shown promise in regenerative medicine due to their ability to differentiate into diverse cell lineages and exhibit regenerative properties. However, the lack of standardized procedures for isolating and cultivating MSCs has led to heterogeneous cultures containing stem cells with different multipotent properties. Despite this, non-clonal stromal cultures obtained from bone marrow and other tissues are currently used as sources of putative MSCs for therapeutic purposes. A comprehensive review of MSC-based clinical trials conducted worldwide is presented, which scrutinizes the biological properties of MSCs, elucidates recent clinical findings and clinical trial phases of investigation, highlights therapeutic effects of MSCs, and identifies principal criticisms of their use. Clinical trials using MSCs are analyzed for representative diseases such as hematological disease, graft-versus-host disease, organ transplantation, diabetes, inflammatory diseases, and diseases in the liver, kidney, and lung, as well as cardiovascular, bone and cartilage, neurological, and autoimmune diseases. This article was authored by Tiziana Squallaro, John Franco Paluzzo, and Umberto Galdorisi. We are article.tv, links in the description below.