Organic

To put it as simply as possible organic crops are raised without using most conventional pesticides, petroleum-based fertilizers, or sewage sludge-based fertilizers. Animals raised on an organic operation must be fed organic feed and given access to the outdoors. They are given no antibiotics  or growth hormones."

Natural 

Food that has undergone minimal processing and contains no preservatives or artificial additives.

Understand however, if the label reads "Natural flavor" this does NOT mean it's without chemicals.