A B complex water-soluble vitamin. It functions as a coenzyme in the breakdown and utilization of protein, together with vitamins B12 and C. Folic acid functions as a carbon carrier in the formation of heme, the iron-containing protein found in hemoglobin, necessary for the formation of red blood cells. In addition, folic acid is needed for the formation of nucleic acid which is necessary for the growth and reproduction of body cells. Disease prevention or therapy with sulfa-containing drugs interfere with the bacteria in the intestinal tract which are responsible for manufacturing folic acid. As a result, a deficiency of this vitamin may occur.