Upon undergoing biomonitoring, the most active dichloromethane extract retrieved fromSenna macrantheraroots led to the isolation of three main compounds: emodine, physione, and chrysophanol. In this sequence, these compounds revealed a potential antibacterial activity againstStaphylococcus aureusstrains isolated from animals with mastitis infections with minimum inhibitory concentration (MIC) values of 20, 90, and 90 μg mL⁻¹, respectively. Therefore, an herbal soap was also produced from this same active extract. This soap was testedin vitrousing gloves contaminated by animals with bovine mastitis that had been discarded after use by milkers and showed similar results to previously tested compounds. These results indicate the potential of this plant as an alternative veterinary medicine for the production of antibacterial soaps that aimed at controlling bovine mastitis infections in small Brazilian farms.