ATLANTA - Cough and cold medicines send about 7,000 children to hospital emergency rooms each year, the U.S. government said Monday in its first national estimate of the problem.

About two-thirds of the cases were children who took the medicines unsupervised. However, about one-quarter involved cases in which parents gave the proper dosage and an allergic reaction or some other problem developed, the study by the U.S. Centers for Disease Control and Prevention reported.

The study included both over-the-counter and prescription medicines. It comes less than two weeks after the U.S. Food and Drug Administration warned parents that over-the-counter cough and cold medicines are too dangerous for children younger than 2.

The study's findings about the proportion of properly dosed kids who end up in the ER is likely to contribute to FDA discussions about recommendations of cough and cold medicines in the 2-to-6 age group, CDC officials said.

CDC researchers gathered case reports of children 11 and under who had taken cough and cold medications and wound up in 63 hospitals studied in 2004 and 2005. They used that number to come up with the national estimate.

About 1,600 of the estimated 7,100 children are under 2, so the FDA's guidance — if followed — should reduce such ER cases by 23 percent.

Nearly two-thirds of the cases involved kids ages 2 to 5, the CDC found.

"The main message is no medication left in the hands of a 3-year-old is safe," said the CDC's Dr. Melissa Schaefer.

Many of the ER case reports were not specific about symptoms, and the researchers did not follow cases through to conclusion. So they did not know if — or how many — deaths resulted, said Schaefer, an epidemiologist who was the study's lead author.

For the children whose symptoms were reported, allergic reactions like hives and itching were most common, and neurological symptoms like drowsiness and unsteady walking were next, she said.

Most of the medicines involved were liquid combinations of cough and cold treatments, CDC researchers said.

Of the children who reportedly got the right dose of medication, about a third were younger than 2, but more than half were ages 6 to 11, the study found.

Some children suffer side effects from medications, so those results aren't necessarily unexpected, Schaefer said. The FDA will have to balance data like this against the medicines' benefits and other factors, she added.

"What we gave them was a piece of the puzzle," she said.

Parents should not encourage children to take medicine by telling them it's candy, and parents should also avoid taking adult medications in front of kids, CDC officials said.

The study tells a story of the misuse of medications, said Linda Suydam, president of the Consumer Healthcare Products Association, a trade group that represents manufacturers and distributors of over-the-counter medicines.

"These medicines are safe when used as directed, and this government review underscores the importance of educating consumers — especially those with small children — on the safe use and safekeeping of medicine," Suydam said, in a prepared statement.

The study was published online Monday. It will appear in the April issue of Pediatrics, a journal of the American Academy of Pediatrics.