WASHINGTON — A top government health official rejected the idea of an immediate ban on cough and cold medicines for young children, saying it might cause unintended harm.

Food and Drug Administration officials at a public hearing Thursday said they need to gather more data on whether over-the-counter remedies are safe and effective for children ages 2-6.

The FDA is also worried that a ban — as sought by leading pediatricians' groups — might only drive parents to give adult medicines to their youngsters.

"That is a concern for us," said Dr. John Jenkins, who heads the FDA's Office of New Drugs. "We do not want to do something that we think will have a positive impact, only to have an unintended negative. That could be an even worse situation."

With a new cold season coming, pediatricians are urging the government to demand a recall of over-the-counter cough and cold medicines for children younger than 6. The effectiveness of the medicines in children was never scientifically established, critics say, and problems with the drugs send thousands of kids to the emergency room every year.

"When a treatment is ineffective, its risks — unless zero — always exceed its benefits," Dr. Michael Shannon of Children's Hospital in Boston told the FDA panel.

The FDA this year warned against giving OTC cold medicines to children younger than 2. At that time, officials said they expected to decide by spring on recommendations for youngsters up to 11. Now the agency is seeking more advice from doctors, industry and consumers — and officials are not giving a timetable for a decision.

U.S. families spend at least $286 million a year on such cough and cold remedies for children, according to the Nielsen Co. market research firm. In any given week the medicines are used by an estimated 10 percent of all children, with the biggest exposure among 2- to 5-year-olds, a recent Boston University report found.

But colds usually clear up on their own after a few days. Many doctors say rest and plenty of fluids are what it takes to get over a cold.

The industry says OTC medicines have been used for decades in treating kids' colds and are safe for those older than 2. Nonetheless, manufacturers are planning to carry out new studies involving the most common ingredients in the medications. The companies voluntarily stopped selling cough and cold medicines for babies and toddlers last fall.

FDA advisers said that was not enough and recommended that the drugs not be used for children younger than 6. An expert panel said children older than 2 could keep taking the medications while studies are undertaken to settle scientific questions about safety and effectiveness.