When giving medication to a child, you should only use products that are formulated for that child's age range. For example, the FDA does not recommend medication for cold or cough symptoms for children under 2 years old. Aspirin should not be given to anyone under the age of 19 without first consulting a doctor. Check the label to determine which products are appropriate for children. Never give adult medication to a child.  When determining the appropriate dosage, it's best to go by your child's weight. Appropriate dosage information is available on the packaging of OTC medications. If you have any questions or concerns, call your pediatrician for further clarification.