The US Food and Drug Administration is advising consumers to stop using liquid-filled children's teething rings manufactured by RC2 Brands (the first years) because the liquid contained in these rings is contaminated with bacteria that may cause serious illness if swallowed by babies, enters the lungs, or is absorbed through a cut in the mouth.

The risk of illness is especially high in infants whose immune systems are compromised by underlying issues such as malnutrition, blood problems, or as a result of cancer therapy, according to the FDA release.

RC2 Brands (the first years) stopped distributing the teethers and began a recall of these products in January 2006.

"FDA is closely monitoring the recall to ensure that all these teething rings are removed from the market and that consumers are alerted to the problem. The agency is also taking a careful look at other RC2/The First Year products to determine if any others are contaminated with the bacteria," said Dr. Daniel Schultz, director of FDA's Centre for Devices and Radiological Health.

The teething rings were sold nationwide between July 2005 and January 2006 at major retailers, and grocery, drug, and specialty stores.