Serotonin is a well-known human neurotransmitter. In plants, it is known to be involved in flowering, senescence, and development. Recent publications suggested that serotonin levels are modified in response to biotic and abiotic stresses. Setaria viridis (green foxtail) is a resilient crop with good yields in dry and marginal land. We recently reported that S. viridis synthesizes serotonin in response to aphid feeding. However, the effect of abiotic stresses on serotonin amount in S. viridis is still unstudied. The goal of my project is to understand whether serotonin biosynthesis is involved in adjustment to abiotic stresses. For salinity stress, Setaria seedlings were exposed to sodium chloride, and the serotonin level was detected using GC-MS. The result revealed the induction of serotonin under salt stress. To elucidate the effect of drought, plants were exposed to 20 % polyethylene glycol (PEG), and the relative water content was measured. The results showed lower relative water content of the plants treated with PEG. Currently, I’m measuring the levels of serotonin under drought stress. In the future, I will perform an aphid bioassay on plants exposed to both salt and drought stresses and will examine the effect of these stresses on the plant’s metabolism and physiology. Our findings will reveal how Setaria plants respond and adapt to the combined stress of abiotic and biotic stresses, which facilitate the development of crops with greater tolerance to stress conditions.