Background: The development of antibiotic resistance as well as the present adverse side effects of several of the commercially available antibiotics have necessitated the screening of plant extracts in quest of novel medications. This study evaluated Ocimum gratissimum (O. gratissimum) (Linn.) antibacterial potency against bacteria associated with gastroenteritis. Methods: The collection and preparation of plant material, phytochemical analysis, MIC and MBC calculations, bacterial isolation and susceptibility testing, gas chromatography-mass spectroscopy (GC-MS) analysis, and bacteria susceptibility testing were all carried out in accordance with the standard protocol. Antibiotic sensitivity patterns and antibacterial susceptibility tests were studied using the disc diffusion method and the agar well diffusion method, respectively. Results: In the GC-MS study, three important bioactive compounds were identified: N-hexadecanoic acid, 6 octadecenoic acid, and 9, 12 octadecadienoic acid (14.98, 8.05, and 13.15 percentage composition, respectively). The remaining compounds were minor in nature. Ethanol extract showed the highest zone of inhibition of 29.67±0.33mm against Escherichia coli (E. coli) and the least antibacterial activity against Shigella flexneri with 13.67±0.33 mm diameter zone of inhibition at 100mg/ml. N-hexane extract lacked any antibacterial effects at 100mg/ml. The MBC values ranged between 50 and 100 mg/ml, while the MIC values ranged from 12.5 to 100mg/ml. Conclusion: From this study, O. gratissimum ethanol extracts have the strongest antibacterial activity against E. coli when compared to other extracts in the treatment of bacteria associated with gastroenteritis. N-hexadecanoic acid, 6 octadecenoic acid, and 9, 12 octadecadienoic acid all have significant biological properties that can be used to combat gastroenteritis-causing bacteria.