Nov. 2, 2009 (United Press International) -- The U.S. Food and Drug Administration says it has warned the Procter & Gamble (NYSE:PG) Co. two of its products are being marketed illegally.

The FDA said the Cincinnati company's Vicks DayQuil Plus Vitamin C and Vicks Nyquil Plus Vitamin C are illegally marketed combinations of drug ingredients and a dietary ingredient.

Both of the over-the-counter medicines, which contain vitamin C in addition to several drug ingredients, are marketed as treatments for cold and flu symptoms.

The FDA said the combinations of drug ingredients and dietary ingredients cannot be legally marketed because there are insufficient data to show vitamin C is safe and effective in preventing or treating the common cold.