Have you ever eaten ice cream, chocolate milk, apple pie or salad dressing? If so, then you have eaten kelp! Unlike other kinds of seaweed, like red algae, which are used directly as food, kelp is not usually eaten directly by humans. Instead, certain compounds are extracted from the kelp and then used in other foods. Algin is one of these compounds and is used to help make different ingredients stick together and form gooey gels. Algin and other compounds from kelp are also used in other products used by humans, like paint, cosmetics and some drugs.