Heat stress is exposing birds to degrees of temperature higher than the optimal, which results in numerous health problems i.e. respiratory deficits decrease feed intake and thus lower weight at marketing age. Heat stress represents one of the most important factor that has negative effects on poultry production. Heat stress also leads to negative effects on the carcass properties and thus lower meat quality, consequently leads to severe shortage in the market. Most important solutions are using feed additives that have positive effects for resisting thermal stress. Betaine that has several other beneficial effects of mild heat stress. Most of the trials were reported slight positive effects; however, systematic results were rare. Since there are almost unlimited possibilities concerning dosage and products of betaine there is still more research required. Nevertheless, there is still further research under more standardized conditions needed to evaluate the right dosage and combination as well as the exact mechanism of actions of anti-stress effects of betaine.