This thesis studies the effect of a protease inhibitor known as z-FA-FMK on the growth of the intracellular parasite Toxoplasma gondii. During infection, the parasite can change from active infectious form to dormant form and eventually form cyst. Dormant parasites in cysts are difficult to be eradicated by currently available drug treatment. In this thesis, we found that z-FA-FMK inhibits Toxoplasma gondii growth and induce them to form cyst through inducing nutrient starvation.