An Allergic reaction is a condition that occurs when the food immune system overreacts to the allergen. These reactions are specific and differ from person to person. Allergy to Mustard is also one of the rarest allergens. It occurs in people who have other allergies such as atopic dermatitis. Mustard allergy usually starts before the age of three years. Mustard allergy often produces severe symptoms and effects skin and gastrointestinal tract. Food products having mustard mention it as an ingredient on their label because it can affect gastrointestinal track which is hazardous for life. Other symptoms i.e. developed within an hour of eating mustard is wheezing, dizziness, diarrhea, swelling of lips and face etc.