06/12/2025
Questions (and complaints) about tear staining in dogs is something I hear frequently. That rusty brown coloring takes over the hair at the dog's inner eyes. But what causes it?
Most of the time tear staining is normal and not a medical concern (if your dog has a lot of "goop" or you are concerned, please check with your veterinarian). Tear staining occurs when a chemical called porphyrin, a breakdown product of blood in the tears, interacts with the light and is oxidized. This causes a brownish stain of the hair at the inner aspect of the eye that "dyes" the fur.
I strongly advise skipping over most of the over-the-counter products available to "treat" tear staining. Many of these products contain an antibiotic (tylosin).
The antibiotic is unnecessary (and could contribute to antibiotic resistance) because it is NOT a bacteria problem. Plus, many of these products don't specify how much antibiotic is in them - so the dose could be wrong for your pet.
Here's what I recommend instead:
Gentle daily washing of this area of your pet’s fur. All you need is warm water and a paper towel, cotton ball, washcloth, or even a soft toothbrush to gently comb the area.
