Related Clues:

• Litmus reddeners
• See 27-Across
• Fatty ___
• Stomach ___
• They have low pH's
• Tummy troublers
• Niacin and vitamin C
• H2SO4 and such
• Base antagonists
• Certain vitamins
• Etcher's supply
• Chem lab collection
• HCl and others
• They have pH's of less than 7
• Caustic liquids