Acetarsol, due to the ability to block sulfhydryl enzyme systems, disrupts the metabolic processes of the protozoa (including trichomonads, amoebae), and some spirochetes. To prevent the resorption of the drug (and possible intoxication), it is necessary to maintain the acidic environment of the vagina. Glucose (dextrose), which is part of the drug, is a nutrient substrate for lactobacilli of normal vaginal microflora. Lactobacilli decomposes glucose to form lactic acid, providing an acidic environment of the vagina. Boric acid also supports the acidic environment of the vagina.