Mustard Allergy

Mustard is one of the 14 major allergens (food types). It must be mentioned either on a label or through information provided, such as a menu, when it is used as an ingredient in any food. Because mustard is sometimes a masked or hidden allergen in foods it is important to know that it may not be obvious by sight, taste or smell.


Mustard allergy is more prevalent where mustard plays a large part in the diet, in countries such as France. It is unknown how common mustard allergy is in the UK as there has been limited research or data collection. The number of people affected by mustard allergy is therefore unknown. However, what we do know is that mustard allergy has been reported for many years. In addition, there has been an increase in the use of spices, including mustard, in different food types  in the last few years which increases the likelihood of being exposed to mustard in our diet.

Related Resources

As one of the top 14 allergens, we have provided this Factsheet to help answer your questions.

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Cross reactivity

Mustard allergy can occur when there is a cross-reaction between a pollen allergen and a food allergen. Allergens are proteins that are recognised by the immune system as harmful in some individuals.

Mugwort-mustard allergy syndrome occurs when a person becomes sensitised to a weed called mugwort (when the allergen they breath in results in the development of allergic symptoms). It affects those with hay fever who have an allergic reaction to foods eaten from the wider mustard family, including members of the Brassicaceae/ Cruciferae family such as white mustard (sinapis alba) and Indian mustard (Brassica juneca). Mugwort allergy is not common in the UK so this type of cross-reaction is rare.

Sign and symptoms

Mustard allergy can affect people of any age. As with any food allergy the signs and symptoms can vary and will affect people differently.

Allergy symptoms that have been reported in mustard allergy range from mild symptoms such as pollen food  syndrome, hives and vomiting to the most severe form of an allergic reaction (anaphylaxis) requiring the use adrenaline.

Mustard in the diet

Mustard added to a food as a sauce or a condiment will naturally depend on an individual’s like or dislike.

Mustard is used in many styles of cooking including, but not limited to, Chinese, Japanese, Indian, French, Middle Eastern, Eastern European and Italian. It should also be noted that mustard is often an added ingredient to enhance flavour, for thickening and stabilising abilities. It can be found in processed foods including baby food, highlighting the importance of reading ingredients labels carefully.

Types of mustard

Mustard seeds are produced by the mustard plant which is a member of the Brassica family. Seeds can be white, yellow, brown or black. Whole seeds can be used in a variety of ways in cooking including roasting, marinating or as an addition to pickled products. Whole, ground, cracked or bruised mustard seeds are mixed with other ingredients to make table mustard.

Mustard Powder Seeds may be ground down to a powder or flour and used widely in a variety of styles of cooking.

Mustard is made by combining different mustard seeds. The mild white or yellow seeds and the brown and black seeds being (stronger) which are added to other ingredients such as vinegar. The yellow colour of some mustard types is from the addition of ingredients like turmeric or other colourants. There are many varieties of prepared table mustard available. Sometimes mustard may be labelled as mild or hot and this depends on the type of seed combinations used to create the heat strength.

Mustard greens

In addition to the seeds, the leaves and stem of some varieties of mustard plants are edible and may be used as a salad leaf or vegetable.

Table mustard varieties

American style · Dijon · English · French · Hot dog mustard · Sweet mustard · Wholegrain mustard


Barbeque sauce · Cumberland sauce · Curry sauce · Ketchup/tomato sauce · Mayonnaise · Mustard sauce · Honey & mustard sauce · Salad dressings · Salad oils · Vinaigrettes · Mustard oil


Pickled onions (mustard seeds often in the vinegar · Pickled gherkins · Pickles · Chutneys · Piccalilli

Other food sources

Processed deli meat · Sausages · Meat that has a coating or marinade which contains mustard · Stock cubes or liquid stock

Mustard greens

Baby mustards · Chinese leaf mustard · Indian mustard · Kai Choi · Jie cai · Leaf mustard · Mostaza

This list is not exhaustive and aims to highlight some of the common foods containing mustard. The key is to read labels carefully and ask questions about the mustard content in prepared foods when eating away from home.

Diagnosing mustard allergy

If you suspect you have had an allergic reaction to mustard it is important to seek medical advice without delay. A follow up appointment with your GP is recommended to determine if the symptoms you have experienced after exposure to mustard are suggestive of a food allergy. You may then be referred for allergy testing which may include skin prick testing and/or a specific IgE blood test.