FDA’s Center for Veterinary Medicine (CVM) is taking the first step toward rescinding its approval of the use of carbadox to treat swine because the regulatory agency says the drug may leave trace amounts of a carcinogenic residue and could pose a potential risk to human health from pork consumption, especially pork liver.

“The manufacturer of carbadox has failed to provide sufficient scientific data to demonstrate the safety of this drug given evidence that carbadox may result in carcinogenic residues,” says Michael Taylor, FDA deputy commissioner for foods and veterinary medicine. “As a result, FDA’s Center for Veterinary Medicine is taking legal action to remove this product from the marketplace.”

FDA is not recommending people make changes in their food choices while the agency is working to remove carbadox from the market. Potential cancer risks are based on an assumed lifetime of consuming pork liver or other pork products containing carbadox residues, and short-term changes in diet are unlikely to affect a person's lifetime risk. However, FDA says removal of the product from the market will reduce the lifetime risk to consumers, which is why CVM is taking this action. Pork liver is used to make liverwurst, hot dogs, lunchmeat and some types of sausage. In general, eating a varied diet may reduce the potential negative effects of eating too much of any one food.

CVM is committed to working with pork producers to minimize impacts on the swine industry. Carbadox was first approved in the early 1970s for use in swine to control swine dysentery and bacterial swine enteritis. It has also been used for weight gain and feed efficiency. To remove its approval, CVM must first file a Notice of Opportunity for Hearing, which it issued today. The notice provides the manufacturer of carbadox with an opportunity to request a hearing within 30 days on whether the approval should be withdrawn.