Antimicrobial resistance is a major cause of significant morbidity and mortality globally. Ethnomedicine provides
avenues for identification of compounds with antimicrobial properties and potential new antibiotics. Callistemon
viminalis is an ethnomedicinal plant used in Jamaica to treat intestinal illnesses. Methanol, hexane and aqueous
extracts of Callistemon viminalis were tested against eight common bacteria and a single fungus of medical
importance using a quantitative agar well diffusion test and tube dilution assay. All plant extracts showed
antimicrobial activities against the selected microorganisms; the methanol extracts were most effective. The aqueous
extract on the other hand, was very effective as a bactericidal agent against the intestinal pathogens. These results
support the ethnomedicinal claim that C. viminalis is an effective treatment for bacterial causes of intestinal illnesses.