Various diseases are caused by different pathogenic microorganisms. Antibiotics are used for treatment of infectious diseases, but indiscriminate use of it leads development of resistant microbes. It is required to find new ways to fight against diseases causing microbes. One of them is combination therapy of plant extract with antibiotics and this may be effective for treatment of various diseases. This study has been carried out to evaluate interaction of methanol extract of Cinnamomum zeylanicum with different antibiotics against bacteria and fungi.