Catechu, obtained from Acacia catechu heartwood is one of the important constituent of Paan, in which it is used as an astringent. The present study investigated in vitro the effect of various concentrations of catechu on oral microflora. The effect on prominent oral pathogenic bacteria, Enterococcus faecalis, Streptococcus mutans and yeast, Candida albicans was studied. The saliva samples, before and after the use of catechu were taken and the microorganisms were counted on plate count agar. The results showed significant decrease in the CFU count per ml of saliva and the population of the pathogenic bacteria also reduced significantly. The results showed that catechu was effective on oral pathogens and hence it can be stipulated that chewing of pan with catechu may be useful to maintain oral health.