ASPCA Sheds Light on Toxin Identified as Part of Tests on Tainted Food

Nationwide Pet Food Recall Crisis Continues
March 23, 2007

NEW YORK, March 23, 2007—Based on new reports issued by the New York State Department of Agriculture and Markets that rodent poison was found in laboratory testing of the tainted pet food recalled last week, the ASPCA® (The American Society for the Prevention of Cruelty to Animals®), through its Animal Poison Control Center (APCC), has the following information to provide to the public:

Aminopterin, a toxin found in some rodenticides available outside the USA, is a folic acid antagonist, i.e. it disrupts the body’s ability to utilize folic acid. In animals, this can result in loss of appetite, diarrhea and weight loss. It may also cause leucopenia, which is a reduction in white blood cells, as well as birth defects.

Aminopterin is closely related in chemical structure and mechanism to a drug called methotrexate, which is used to treat some cancers, both in humans and animals. Renal failure has been reported in human patients receiving methotrexate. We do not know if aminopterin can cause renal failure in pets. 

Based on these findings, the ASPCA does not recommend any change in treatment of animals affected; animals currently being treated for kidney failure suspected to be related to the ingestion of the contaminated food should stay on such treatment. Please follow your veterinarian’s advice.

It is unclear at this point in time how this toxin came into contact with the affected food. The ASPCA will continue to analyze the data on calls the APCC receives (which number between 400-700 daily on a wide range of substances), and release any new information it finds immediately.

In addition, pet parents may find the following information useful:

- For a complete list of affected brands, please visit

- The American Veterinary Medical Association has some excellent advice and information on its Web site for both pet parents and veterinarians at

- If your pet shows any signs of illness, including loss of appetite, lethargy, vomiting, diarrhea, changes in water consumption or changes in urination, please consult your veterinarian immediately. If you are unable to reach your veterinarian and suspect your pet is gravely ill, you may call the ASPCA’s Animal Poison Control Center at (888) 426-4435 for emergency advice (a $55 fee applies).

- To report adverse actions or other problems to the FDA, pet parents can go to
to contact the FDA complaint coordinator in their state.