The U.S. Food and Drug Administration (FDA) is cracking down on some makers of over-the-counter products that are marketed to remove the tear stains in dogs and cats because they are misusing an antibiotic.

The agency issued a warning letter Friday to the makers of Angels’ Eyes, Angels’ Glow, Pets’ Spark and exported products Glow Groom and Health Glow because they have not been reviewed by the FDA for safety and effectiveness, it says. The products contain the antibiotic tylosin tartrate, which is not approved for use in dogs or cats, nor for the treatment of conditions associated with tear stains, the FDA says.

Tear-staining, commonly caused by epiphora — excessive tear production — can produce reddish-brown streaks under a dog’s eyes, especially in certain breeds. Excessive tearing or discharge from the eyes can also be a symptom of a serious eye-health problem.

The FDA says that if the products stay on the market, the agency may seize them or file an injunction against the companies that make them or distribute them.

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To read the FDA letter to I’m a little Tea Cup, maker of Angels’ Eyes, click here.

To read the FDA’s warning letter to Angel’s Glow, made by Blanc du Blanc, click here.

To read the FDA’s warning letter to Petaware, the maker of Pets’ Spark, Glow Groom, and Health Glow products, click here.