Severe COVID-19 cases are mostly due to severe inflammatory reaction and cytokine storm, which may lead to multiple organ failure and death. Until recently, there is no proven effective treatment for severe COVID-19. Mesenchymal stem cells (MSCs) have anti-inflammatory and regenerative properties. Therefore, they are supposed to work on COVID-19, which has failed to recover using other treatments. Therefore, studies are needed to determine the best tissue source of MSCs, the dose, repeat, and route of administration. For this review, we searched various databases, i.e. Pubmed, Science Direct, Springer, and WHO website using keywords: “mesenchymal stem cells” and “COVID-19” at 7 May 2020, without time limits. Various clinical trials on the use of MSCs for COVID-19 were registered, and initial results were reported. Initial results were promising but should be interpreted cautiously, as one was a case report, another one was case series, and one was a preliminary study of seven treated patients compared to three controls, where the baseline conditions were unequal. Therefore, well design randomized clinical trials are needed to get more robust prove
