Phytochemicals are naturally occurring, biologically active compounds found in plants that offer numerous health benefits beyond those of basic nutrients. These compounds play vital roles in protecting plants from environmental stressors and pathogens, and many exhibit therapeutic potential for human health. Psidium guajava L. (guava), a tropical plant commonly found in Nigeria, is widely recognized for its nutritional and medicinal properties. While the fruit is popularly consumed, the leaves also contain valuable phytochemicals with potential antimicrobial effects. This study investigated the antibacterial activity of ethyl acetate and aqueous extracts of Psidium guajava leaves against Escherichia coli strains isolated from stool samples of children presenting with diarrhea at a specialist hospital in Gusau, Nigeria. Phytochemical screening revealed the presence of key bioactive compounds such as flavonoids, tannins, saponins, and alkaloids, which are known to contribute to antimicrobial activity. The results demonstrated that both ethyl acetate and aqueous leaf extracts exhibited inhibitory effects on the growth of E. coli, with the ethyl acetate extract showing higher antibacterial potency. These findings support the potential use of guava leaf extracts as a natural alternative or supplement to conventional antibiotics in the treatment of pediatric diarrheal infections caused by E. coli