The study analyzed the effect of common poultry medicines on ethanol fermentation using Saccharomyces cerevisiae. Various concentrations of Avatec, Cygro, Robenz, and Monesine were tested in batch reactions at 33°C and 36°C. Results showed that higher concentrations of Robenz and Avatec decreased sucrose concentration over time, suggesting reduced bacterial contaminants and increased yeast growth. Specifically, Robenz 100 ppm/L and Avatec 1000 ppm/L at 33°C, and Avatec 100 ppm/L at 36°C minimized bacterial growth. However, very high medicine concentrations also reduced yeast. Further analysis is needed to differentiate sucrose consumption by yeast versus bacteria to