A Food and Drug Administration investigation has prompted a nationwide recall of Miracle Leg Paint, a treatment for horses sold over the Internet, because it contains mercury, which is toxic to horses and to people.

The government is cautioning horse owners that have purchased the product not to use it. The FDA says they should instead contact waste-management authorities to find out how to destroy it without harming animals, people, or waterways.

Miracle Leg Paint, a product by Equine Miracle Corp., a Grapeland, Texas, company owned by Georgia Brown and her husband, includes a mercuric chloride blistering agent.

A veterinarian in Alabama contacted the FDA in late April after autopsying a horse whose owner had applied Miracle Leg Paint. Dr. Stephen Sundlof, the FDA's veterinary medicine chief, said that there is no evidence that the product played a part in the horse's death, but the information did ignite an FDA investigation, the Associated Press reports.

Sundlof said that Equine Miracle Corp. was selling an unapproved drug. The company agreed on a recall on Thursday.