Food allergies and food intolerance are often used interchangeably because they can have some of the same signs, but they are two very different things. When you are allergic to a food, your immune system reacts and affects many organs in the body. Sometimes allergic reactions can be severe and even life threatening. Food intolerance reactions are usually less severe and often only cause digestion problems. If you are allergic to something you cannot consume the food at all, whereas one can ingest foods if you have an intolerance although it will cause discomfort at some level. Food intolerance can be due to many different things like sensitivity to food additives, irritable bowel syndrome, celiac disease, or the lack of enzymes required to fully digest food. If you have a reaction after eating a certain food, you should consult a physician so that they can determine if you have a food allergy or are intolerant to that specific food.