CFR > Title 21 - Food and Drugs > CHAPTER I—FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES > SUBCHAPTER E—ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS (parts 500 to 590) > PART 556—TOLERANCES FOR RESIDUES OF NEW ANIMAL DRUGS IN FOOD > SUBPART B—Specific Tolerances for Residues of New Animal Drugs (§556.34 to §556.770) > 556.685—Sulfaquinoxaline.