Exposure to high environmental temperatures is considered to be one of the most deadly conditions, affecting human and animal health. Relatively small increase in internal temperature can lead to injury and even death. Prevention of the gut permeability would offer a significant benefit in mitigation of the heat stress impact. Gut microbiota is critical in keeping mucosal barrier function. Stability of gut microbiota determines the ability of the organism to tolerate stress. Thus, modulating the intestinal microbiota by probiotics may be a novel, non invasive therapeutic approach for prevention of heat stress related adverse effects.