Yeast, Saccharomyces cerevisiae is the causative organism in the fermentation of Asavas and Aristas, popular Ayurvedic dosage forms. The effect of some phytochemical constituents on the ability of yeast to hydrolyse fluorescein diacetate to fluorescein has been investigated with the help of HPTLC and it-is found that monoammonium glycyrrhizinate enhances the enzyme activity of yeast. Such constituents may have effect on the rate of alcohol production.