Herbal medicines constitute a potentially important resource for new and safe drugs for the management of microbial infections and other diseases. This study aimed at examining whether or not crude plant extracts of Hugonia casteneifolia, Commiphora sponthulata and Raphidiocystis chrysocoma have antimicrobial activities on some pathogenic bacterial isolated from sick domesticated animals. Agar diffusion technique was used to determine the inhibition of microbial growth and broth dilution technique was used to determine MIC and MBC. The study has shown that R. chrysocoma extract is very potent against Streptococcus agalactiae, Staphylococcus aureus and Escherichia coli, H. casteneifolia is potent against S. agalactiae and S. aureus, and C. sponthulata extract is potent against Salmonella gallinarum only. All the three plant extracts are non-cytotoxic. This is the first scientific evaluation of the veterinary medicinal potential of the H casteneifolia, C. sponthulata and R. chrysocoma from Tanzania, providing the baseline for further investigations towards discovering new drugs.