The government of Hong Kong has asked fastfood giant McDonald’s to withdraw a seasoning used in the company’s French fries because it could contain a banned artificial sweetener.

The government said that the label on McDonald’s Honey BBQ seasoning listed stevioside, an artificial sweetener banned in Hong Kong because of fears it may be carcinogenic, as an ingredient, reported Reuters.

“We are testing to see if it is a permitted sweetener or not. Legal action would be considered subject to the results of the test,” a spokeswoman for the Hong Kong food and environmental hygiene department was quoted by Reuters as saying.

Although a link between Stevioside and cancer has not been scientifically proven, the substance has been banned from use as a food additive in many countries.