Parents should not give sniffling babies and toddlers over-the-counter cough and cold medicines — they are too risky for tots so small, the U.S. government was to say on Thursday.

The Food and Drug Administration still has not decided if the remedies are appropriate for older children to continue using, officials told The Associated Press.

Expect a decision on that by spring, the deadline necessary to notify manufacturers before they begin production for next fall's cold season.

For now, the FDA is issuing a public health advisory to warn parents to avoid these drugs for children under age 2 "because serious and potentially life-threatening side effects can occur."

It's not the first warning about cold remedies and toddler: Drug companies last October quit selling dozens of versions targeted specifically to babies and toddlers. That same month, the FDA's own scientific advisers voted that the drugs don't even work in small children and should not be used in preschoolers, either — anyone under age 6.

Thursday's advisory marks the government's first ruling on the issue: Don't give the drugs to children under 2. And it comes now because the FDA is worried that parents have not gotten that message despite all the publicity last fall.

Dr. Manny Alvarez, FOXnews.com managing editor of health, said the ruling is a welcome decision from the FDA that will better ensure the safety of young children.

"Basically, this is the final confirmation on something the FDA had been looking at for quite a while and that is what are the potential side effects of these medicines on children under 2," Alvarez said. "There aren't any studies on children under 2 and, because of ethical concerns, there likely won't be any studies anytime soon."

Alvarez said there were several criteria that went into the FDA’s decision.

"No. 1, the dosification of these medicines for children under 2 is not well-understood and, if you look, most bottles tell parents to consult a physician for young children," he said. "But the pediatricians don’t have any guidelines on how much children this age need, so recommendations are usually made arbitrarily.

"But the second thing is that the metabolisms of children differ from the metabolisms of adults, so there’s no way of knowing how the child will metabolize the medication and what potential side effects it will have,” Alvarez continued.

Finally, Alvarez said there are many misconceptions on the part of parents as to how these medicines work.

"These medicines treat symptoms; they don’t cure a cold," he said. "So if parents think they are curing something with these medicines, they’re kidding themselves. When it comes to small children, keeping them hydrated, monitoring them and consulting a pediatrician are far more important then relying on over-the-counter medicine."

They still may have infant-targeted drugs at home, or they may buy drugs meant for older children to give to hacking tots instead, said Dr. Charles Ganley, FDA's nonprescription drugs chief.

"We still have a concern," Ganley said. "It falls out of people's consciousness. We're still in the middle of cold season right now."

Ganley said he is particularly concerned by recent surveys that suggest many parents don't believe OTC cold remedies could pose a problem, especially if they've used them with an older child who seemed to get better.

Thursday's move is a good first step, said Dr. Joshua Sharfstein, Baltimore's health commissioner, who petitioned the FDA last year to end use of these nonprescription remedies by children under 6, a move backed by the American Academy of Pediatrics.

The reason: There's no evidence that these oral drugs actually ease cold symptoms in children so young — some studies suggest they do no good at all. And while serious side effects are fairly rare, they do occur. Indeed, the Centers for Disease Control and Prevention last year reported that more than 1,500 babies and toddlers wound up in emergency rooms over a two-year period because of the drugs.

"It's one thing if you're curing cancer, but we're talking about a self-limiting illness," said Sharfstein. "If there's really no evidence of benefit, you don't want to risk the rare problem. Then you're left with tragedy that you can't justify."

The drug industry says these medicines are used 3.8 billion times a year in treating children's cough and cold symptoms and are safe for those over 2.

Health groups acknowledge that while low doses of cold medicine don't usually endanger an individual child, the bigger risk is unintentional overdose. For example, the same decongestants, cough suppressants and antihistamines are in multiple products, so using more than one to address different symptoms — or having multiple caregivers administer doses — can quickly add up. Also, children's medicines are supposed to be measured with the dropper or measuring cap that comes with each product, not an inaccurate kitchen teaspoon.

The Associated Press contributed to this report.