U.S. government officials warned consumers on Friday to avoid using toothpaste made in China because it may contain a poisonous chemical used in antifreeze.

Out of caution, the U.S. Food and Drug Administration said, people should throw away toothpaste with labelling that it was made in China. FDA is concerned that these products may contain diethylene glycol.

The agency is not aware of any reports in the United States of poisoning from toothpaste, but it did find the antifreeze ingredient in a shipment at the U.S. border and at two retail stores: a Dollar Plus store in Miami and a Todo A Peso store in Puerto Rico.

Officials said they are primarily concerned about toothpaste sold at bargain retail outlets. The ingredient in question, called DEG, is used as a lower-cost sweetener and thickening agent.

The highest concentration of the chemical found in toothpaste so far was between three and four per cent, but health officials said it does not belong in toothpaste even in small concentrations.

The FDA increased its scrutiny of toothpaste made in China because of reports of contamination in several countries, including Panama.

The agency is particularly concerned about chronic exposure to DEG in children, and in people with kidney or liver disease.