Colgate-Palmolive said the firm "does not and would never use" diethylene glycol (DEG) - used in anti-freeze - as an ingredient.
The scandal follows the discovery of a shipment of Chinese-made contaminated toothpaste in the US.
The US Food and Drug Administration (FDA) said DEG, which is sometimes used as a low-cost but potentially deadly substitute for glycerine sweetener in cough medicines, posed a "low health risk" but did not belong in toothpaste.
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.
The New York-based firm said the fakes are being sold in five-ounce (100ml) tubes, a size not made or sold in the US and that they are labelled made in South Africa.
It said it did not import toothpaste into the US from South Africa.
Misspelled words on the packaging of the tube was another way of identifying the "fake" products, the firm said.
But Colgate-Palmolive confirmed 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.
It also 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.
(BBC)
