Washington - Government health officials said Friday they are reviewing whether popular medicines like Tylenol Plus Cold & Cough and Infant Triaminic Thin Strips are safe and effective in treating children's colds and coughs.

Disclosure of the ongoing review, which will take months to complete, came as critics charged that many over-the-counter cough and cold remedies can harm toddlers and preschoolers. Those critics, including public health officials and pediatricians, are pushing the government for stricter warnings to prevent life-threatening overdoses.

"We have been looking at this issue internally with regard to the safety and efficacy of the use of these products in children," Dr. Charles Ganley, director of the FDA's office of nonprescription drug products, told reporters as he responded to a petition filed Thursday by city of Baltimore officials and others. The review covers medicines that include decongestants, antihistamines, cough suppressants and expectorants.

The petition is far from the first warning about tots using the medicines. The American Academy of Pediatrics began issuing those warnings to parents in 1997. And just two months ago, the Centers for Disease Control and Prevention reported that more than 1,500 toddlers and babies wound up in emergency rooms over a two-year period because of the drugs. The study's authors told parents to consult a doctor before giving the remedies to children under age 2.

In fact, the labels of every cough and cold remedy already caution parents to do just that, said Linda A. Suydam, president of the Consumer Healthcare Products Association, which represents makers of over-the-counter, or OTC, medicines.

"OTC cough and cold remedies have a long history of safety when used according to the label. The most important information for all consumers is that OTC medicines are real medicines and must be used according to the label instructions at all times," Suydam said in a statement.

Still, product packaging often bears images of children apparently much younger than 2, as well as terms like "infant" and "baby." The petitioners called that misleading, adding that the average drug store stocks more than 30 such products.

Concentrated Tylenol Plus Cold & Cough, for instance, includes a picture of a mother and infant, even though its label recommends asking a doctor before using in children younger than 2. Manufacturer McNeil Consumer Healthcare reiterated that advice in a statement. A spokeswoman declined to comment further.

The FDA has never approved dosing recommendations for the 0-2 age group for the drugs. Nor is it known just how much of their various ingredients it would take to injure or kill children that young, according to the CDC.

The petition asks the FDA to go further and require that labels say the products shouldn't be used to treat children younger than 6.

In Maryland alone, roughly 900 children 4 and younger overdosed on the medicines in 2004, according to the new petition. In Baltimore, the medical examiner has linked the products to the deaths of at least four children under 4 in the last five years.

Yet these products have never been proven to benefit children so young, the petitioners argued.

Therefore, "we recommend that families be aware of these risks and not use over-the-counter cough and cold medications for children ages 5 and under," Baltimore officials said.

So what should parents do?

"They should just continue following the dosing that is on the products now. Given the information we have right now, if we thought there was a need to come out with an immediate statement, we would do so," Ganley said.

A 1994 study suggested that parents commonly use the cold and cough preparations to treat their children, who suffer on average from six to 10 colds a year. The Journal of the American Medical Association study found that in a specific 30-day period, nearly 36 percent of all 3-year-olds in the United States were given nonprescription cough and cold medications.

Ganley also acknowledged to reporters that the petition, perhaps unwittingly, asks a much broader question about the efficacy of the drugs when used in children not just to age 6, but up to 12. That's because the efficacy of the drugs in children across the 2-to-12 age group generally has been established by extrapolating data from testing in adults.

It also raises a question about whether the FDA should leave it to doctors to determine when, and at what doses, it is safe and prudent to use drugs in age groups for which the FDA has no information, he added.

"The petition opens some much broader issues than they realized they opened," Ganley said. The FDA is reviewing both questions, he added.