Active Ingredient(s): This section lists the substance(s) that makes the OTC medicine or product work.
Uses: This section tells you what symptoms or illnesses the OTC medicine or product is intended to treat.
Warnings:

This section may provide information about particular medical conditions and certain circumstances where the OTC product may cause harm.
This section tells you when not to use the product.
When to ask your doctor if it is safe to take the medication if you have a certain medical condition(s) or take a certain medication that is listed on the label.
What side effects you may expect from the product
When to stop using the product.
What to do if you are pregnant or breast feeding.

Provides information how to use the product safely.
Often here you will find different instructions for children that may be based on weight or age.
Depending on the medication it may provide a maximal daily dose.

Provides additional safety and storage instructions. You may also find information regarding if the product contains substantial amounts of calcium, potassium or sodium in its formulation.

Inactive ingredients are added to all drug products to make them look and taste appealing, to maintain their shelf life and to help the active ingredients blend together properly.
Often these "inactive ingredients" do not cause harm. However, some people do experience untoward reactions to these ingredients. Thus, if you have a known sensitivity or allergy to a certain "inactive ingredient(s)" (i.e. wheat, soy, milk, dyes etc.) it is important to review this section carefully before using an OTC product.
It is important to note that children that have "Celiac Disease" (a known sensitivity to wheat, rye and barley) must be careful because there is no requirement for companies to place whether or not their product contains gluten on their label. Thus, you may consider calling the company, talking to your pharmacist or going to the following website glutenfree.com to find out whether or not the OTC product contains gluten.