Background: Infectious diseases cause serious health problems worldwide due to multiresistant bacterial strains. Thai traditional formula such as Benchalokawichian remedy has been used to relieve fever, common cold and influenza. The remedy has been scientifically proved for antipyretic and antiseptic activities. However, the remedy and its components have not been fully studied for antimicrobial activity against pathogenic bacteria.
Objective: To determine antimicrobial activity of extracts from Benchalokawichian remedy and its components against clinical isolates by disk diffusion method.
Material and Method: The bacterial strains used in the present study were clinical isolates from Thammasat Hospital, Thailand. The ethanolic and water extracts of Benchalokawichian remedy and its components were screened for antimicrobial activity. The tests were performed in triplicate. The results were recorded by measuring diameter of growth inhibition zone. Means + SD of the obtained results were calculated.
Results: The results of antimicrobial activity demonstrated that the ethanolic extracts of Benchalokawichian remedy and its components were effective against Candida albicans, Gram positive and Gram negative bacteria except some isolates. Tiliacora triandra and Clerodendrum petasites exhibited the most effective antimicrobial activity among other ethanolic extracts. The water extracts of Capparis micracantha, Tiliacora triandra and Harrisonia perforata were able to inhibit the tested strains. Both etahnolic and water extracts of Tiliacora triandra were the only one component of Benchalokawichian remedy that could inhibit the growth of C. albicans.
Conclusion: The present study provides basic knowledge of the antimicrobial activity of Benchalokawichian remedy and its components. Tiliacora triandra and Clerodendrum petasites were the most effective antimicrobial activity among other ethanolic extracts. They are potential candidates to produce medicinal formula for alternative medicine. Further study on minimum inhibitory concentration and minimum bactericidal concentration assay will be carried out in order to obtain more detailed insightful knowledge to develop medicinal products for treatment of bacterial infection and other infectious diseases.

Keywords: Antimicrobial activity, Benchalokawichian, Remedy, Pathogenic bacteria