Your dog’s fur has dark tracks from the tear duct down towards their cheek. It might be brown, or worse, dark rusty red, and if so, it may even smell.
In the following sections, I’ll outline what causes tear stains on your dog and what supplement you can use to manage it.
Cause
Tear stains occur because your dog’s tear production produces too many tears. It can be caused by:
- Ingrown eyelashes
- Eye infections
- Small tear duct openings
- Large tear glands
- Ear infection
- Secondhand smoke
- Poor quality diet
- Inverted eyelid
- Yeast
- Too much iron for your dog
Yeasty Tear Stains
Red tears are caused by a compound called porphyrin. Porphyrins are iron-containing molecules produced when the body breaks down red blood cells. They are removed primarily through feces but are also in urine, tears, and saliva.
And while iron is essential to your dog’s diet, it could be that your dog for whatever reason has more iron in their body than they can handle.
Iron is found in organ meat, muscle meat, spinach, shellfish, legumes, and even pumpkin seeds. It’s also found in your tap water.
Sometimes, the eye discharge turns to yeast. How can you tell?
It could be yeast if the red tear stains also have dark brown, crusty tracks that smell.
And it’s tough to treat tear stains because they are caused from the inside out.
Porphyrins in tear stains are caused by toxic buildup bio-accumulated in the liver.
Porphyrins Are Waste Products From Blood Cells Containing Iron
Porphyrins in tear stains are caused by toxic buildup bio-accumulated in the liver.
Feeding food that has a higher level of iron (like organ meats, fish, shellfish such as oysters and mussels) can increase the iron levels.
Studies have shown that certain drugs such as sulfonamide antibiotics can trigger porphyrin levels to go up.
Where Are Sulfonamides?
Sulfonamides are antibiotics used to treat animals raised in commercial farms. These antibiotics are necessary to keep the animals growing and healthy.
Sulfonamides are highest amount in pork, pork liver, and kidney
The Liver And Sulfonamides
Our dog’s liver filters all toxins, but porphyrin levels also go up when the load is too high due to sulfonamides.
One way to tackle this is to feed grass fed pork. And while this may seem logical, grass fed pork isn’t readily available to most dog parents.
And so the next logical approach is to support the liver so it can better handle the porphyrins.
Goal: Treat Externally and Remove Excess Toxins In The Liver and Remove The Co-Factor Tear Production Depends On
External Treatment
- Wipe face twice a day with damp washcloth
- Wipe face with contact lens solution
- The boric acid in the contact lens solution oxidizes the iron in the porphyrins and may lighten the staining. After washing the face, always dry the area with a clean towel to prevent ulcerative dermatitis secondary to wet skin.
- Use Vitamin C to clean tear stains.
- You can also use a liquid vitamin c to wipe and lighten the tear stains.
Treat From The Inside Out
- Glass or steel bowls – not plastic
- Milk Thistle
- Feed milk thistle for three weeks and then take a week off. Repeat cycle as needed.
- Liver Support Diet
- Buy better quality pork meat and organs
- Look to buy better quality pork if it’s accessible and affordable to you.
- Do a yeast cleanse
Remedies That I Don’t recommend
- ACV
- Tylosin, makeup remover, milk of magnesia, yogurt, hydrogen peroxide, gold bond, or silver, lemon juice, and colloidal silver.

Key Takeaways
Yeasty tear stains have to be treated from the inside out.
- Keep your dog’s fur clean by wiping it twice a day with a wet washcloth
- Use contact lens solution to help lighten the red or rusty tear stains
- Feed milk thistle for three weeks (take one-week breaks) to help support the liver as it cleans out and lowers the levels of the porphyrin.
Resources:
What Causes Tear Stains in Dogs?: The Science of Tear Stains
Tear Stains: The definitive guide