Do Food Coloring or Beet Pulp Cause Red Tear Stains?

We couldn't find any evidence that food coloring or beet pulp causes tear stains. Vets don't know which food ingredients, if any, cause staining in most dogs. The reddish-brown color comes from natural pigments in tears called porphyrins.

Stains usually form because tears spill onto the face instead of draining into the nose. This happens because of eyelid and face shape, a blocked tear duct, or extra tears from irritation such as rolled-in eyelids, extra lashes or allergies. One small 2026 study found certain herbal-extract diets reduced staining, so diet may play a part in some dogs, but that study didn't test dyes or beet pulp.

If the staining is new or your dog squints or rubs his eyes, ask your vet to check his eyelids, lashes and tear ducts. Otherwise, wipe the area daily with a damp cloth, keep the fur trimmed and dry, and avoid tear-stain products that contain antibiotics. Switching foods is fine if you'd like to try it, but there's no need to pay more for that reason alone.

See watery eyes and tear stains.

This is general information, not a diagnosis. Please follow your own vet's advice.