Drug companies say children under 4 should not be given cough and cold medicines.
The industry has been criticized by pediatricians for marketing over-the-counter cough and cold remedies for children under 6 despite a lack of evidence that they work, and reports of safety problems.
A spokeswoman for the Consumer Healthcare Products Association said Tuesday the decision was voluntary and was being made "out of
an abundance of caution."
The companies will also add a warning to their product labels saying parents should not give young children antihistamines to make them sleepy. Antihistamines are used to relieve allergies.
Government health officials said last week the issue needed additional study.