Abstract: The in vitro interaction between a commercial variety of tea [Camellia sinensis L (Ternstroemiaceae)] and some antibiotics was evaluated against Staphyloccocus aureus (S. aureus) and Escherichia coli (E. coli). Synergism against S. aureus was exhibited by cloxacillin and tetracycline, while the effect of gentamycin was indifferent. Additive effect against S. aureus was exhibited by cefotaxime. The effects of streptomycin, ceftriaxone, ceftazidime, ciprofloxacin, ofloxacin and norfloxacin against S. aureus were antagonized. Gentamycin, tetracycline, cefotaxime and ceftazidime exhibited additive effects against E. coli. The activities of streptomycin, ceftriazone, ciprofloxacin, ofloxacin and norfloxacin against E. coli were antagonized. The results suggest a physicochemical basis for the interaction and indicate a potential for clinically relevant interaction when tea is consumed with antimicrobial agents.