This report describes a dog with anemia and ITP, associated with phenobarbital, treated with prednisolone with a good response after association with three intravenous transplantations of 2.5x106 allogenic Mesenchymal Stem-Cells. After the first transplantation, the number of platelets had an improvement, but started to decrease after three weeks. However, the dose of corticosteroid could be reduced. After the second and third administrations, new increases were observed. The platelet count varied from 102,000 to 365,000 until the end of follow-up and without increase of prednisolone doses. Although phenobarbital therapy has been associated with thrombocytopenia, it was not possible to change the anti-convulsant therapy. The response to corticosteroid-based therapy was partial. Cell therapy was followed by an improvement in platelet count with no observed side effects and therefore could be considered safe. Effects on platelet count were transitory, but until the end of follow-up, no severe thrombocytopenia was observed. Based on the observation that platelet numbers dropped a few weeks after cell therapy, more applications would be beneficial in order to maintain higher platelet counts.