Toothpaste sold in US discount stores in four states with the Colgate-label has been found to contain diethylene glycol (DEG), a toxic chemical used as an anti-freezing substance.

Colgate''s website has warned, "There are indications that this product does not contain fluoride and may contain DEG."

Labelling the product as counterfeit, Colgate-Palmolive said it "does not and would never use" DEG as an ingredient, and said it had launched a recall of these toothpaste tubes from discount retail outlets in New York, New Jersey, Pennsylvania and Maryland, where they were discovered.

The company cautioned on its website that the fakes were being sold in five-ounce (100ml) tubes, a size not made or sold in the US. Moreover, the contaminated toothpaste are labelled ''made in South Africa'', whereas Colgate says it does not import toothpaste into the US from South Africa.

Misspelled words on the packaging of the tube were another way of identifying the "fake" products, Colgate warned. Misspellings include "isclinically", "SOUTH AFRLCA" and "South African Dental Assoxiation".

The company has set up a toll-free help line for consumers who suspect they may have purchased counterfeit product.

A shipment of Chinese-made toothpaste, contaminated with the chemical, was recently discovered in the US. The chemical was also found in a batch of Chinese-made toothpaste exports in Nicaragua about two weeks ago, after which the FDA warned consumers to avoid toothpaste exported from China.

According to the US FDA, DEG, which is sometimes used as a low-cost but potentially hazardous substitute for glycerine sweetener in cough syrups, posed a "low-health risk." The watchdog said, the chemical did not belong in toothpaste.

The company said it was contacting all its accounts that handle Colgate across the US to ensure they have no counterfeit stock and would work with the American Dental Association and American Dental Hygienists to help dental professionals answer patient questions.

"We will spare no effort to help consumers avoid counterfeits and support regulators in their efforts to remove these products from the marketplace," said Colgate-Palmolive chairman and chief executive Reuben Mark.