GSTM1 and Pyoderma: In the present study, RBCs, Hb, PCV and WBCs were returned to their normal values after topical application of different concentrations of A. vera gel ointments 20% and 40% on dogs’ pyoderma thus could be explained by A. vera may increase erythropoiesis process and also increase leukocyte infiltration as a part of immunomodulation [24].