Introduction: J. Communi sberry is a high antioxidant fruit which is used in several traditional medicinal systems to treat a variety of diseases including rheumatism, arthritis and gout.This study was undertaken to examine the inhibitory activity of J. communis berry extracts on the growth of several bacteria associated with autoimmune inflammatory disease, and to test their ability to block CaCo2 and HeLa cancer cell proliferation. Methods: J. Communis solvent extracts were preparedusing solvents of varying polarity. The extracts were investigated by disc diffusion assay for the ability to inhibit the growth of a panel of pathogenic bacteria associated with autoimmune inflammatory diseases. Their MIC values were determined to quantify and compare their efficacies. Inhibitory activity against CaCo2 and HeLa human carcinoma cell lines was evaluated using an MTS colorimetric cell proliferation assay. Toxicity was determined using the Artemia franciscana nauplii bioassay. Results: The methanol, water and ethyl acetate J. communis berry extracts displayed moderate to potent growth inhibitory activity against bacterial triggers of rheumatoid arthritis, ankylosing spondylitis and multiple sclerosis. The methanol and water extracts displayed the broadest specificity, inhibiting the growth of all bacteria tested. The ethyl acetate extract also displayed antibacterial activity, inhibiting the growth of 9 of the 13 bacterial strains (69%). The ethyl acetate extract displayed the greatest potency, with MIC values substantially below 2000 µg/mL for all bacteria which it inhibited. It was most effective at inhibiting the growth of P. mirabilis, P. vulgaris and S. aureus, each with MIC’s ≤ 500 µg/mL. The methanol and water extracts also proved effective at blocking the proliferation of the colorectal cancer cell line CaCo2 and HeLa cervical cancer cell growth, with IC50 values in the 1300-2500 µg/mL range. All extracts were non-toxic in the Artemia nauplii bioassay. Conclusion: The lack of toxicity of the J. Communis berry extracts and their potent growth inhibitory bioactivity against bacteria and HeLa and CaCo2 carcinoma cells indicates their potential in the treatment and prevention of selected autoimmune inflammatory diseases and some cancers.