Even though aquatic life may meet the world’s demand for a significant amount of protein supply, it is not without shortcomings, the most serious of which is stress. The effects of different concentrations of Gynura procumbens on the hematological parameters of acutely stressed Nile tilapia ( Oreochromis niloticus ) were investigated in the present study, and the best concentration was determined , from experiments conducted in a recirculating aquaculture system. Stressed tilapia were fed with Gynura pocumbens extract (0, 0.0005, 0.001 and 0.0015% of feed weight) along with a hydrocortisone stress hormone (0.01% of fish body weight). In this experiment we evaluated blood glucose level, lysozyme activity, phagocytic activity, hematocrit, spleen somatic index and hepato somatic index of the fish. From the preliminary data, Gynura has shown to decrease the levels of blood glucose and brought the levels of serum lysozyme activity and phagocytic capacity in stressed fish to the levels of controlled fish. Chronic research will provide us with a better understanding of how to use Gynura to alleviate stress in fish.