What to Know About Mustard Allergy

Medically Reviewed by Carol DerSarkissian, MD on February 29, 2024
Written by WebMD Editorial Contributors
3 min read

Mustard allergy is a sometimes serious food allergy triggered by mustard. You can find mustard or mustard seeds in prepared mustard and other condiments, salad dressings, spices, seasoning, sauces, soups, pickles, and certain processed foods.‌

Food allergies are common and affect children and adults worldwide. Like all allergies, mustard-related allergies happen when your immune system triggers chemical reactions in your body. In an allergic reaction, your body mistakenly produces antibodies to fight harmless substances. Allergic reactions can range from minor irritations to anaphylaxis, a life-threatening response that affects your whole body.

Small amounts of mustard can trigger life-threatening reactions in hypersensitive people. In others, it may cause mild reactions. 

‌Some of the problems it can cause include: 

Commercial mustard is made from crushed mustard seeds. These seeds contain proteins that trigger the allergic reaction.  

But mustard is not just the yellow condiment that comes in a jar. There are white, brown, and black types of mustard plants. Mustard products are used widely to enhance food’s flavor. Their flavor and smell come from essential oils found in the seeds. Mustard seeds are also used as spices.

Mustard can be found in many manufactured and processed foods. If you’re allergic to mustard, always check the labels of packaged foods. Cold-pressed types of canola and rapeseed oil can also trigger reactions in people sensitive to mustard.

Mustard has long been used as a medication for some conditions. But if you’re allergic to it, touching it can trigger a reaction. Learn what products contain mustard so you can avoid them. 

You can manage some mild mustard allergic reactions with antihistamines. They’re readily available by prescription or over the counter.

If you have a serious mustard allergy, always carry epinephrine autoinjectors. And learn how to use them in case of emergency.

Using an epinephrine injector can make you less likely to need hospitalization. It works by reducing inflammation and relaxing your airways. These actions counteract allergic reactions and increase your survival chances.

Here are a few things you can do to prevent an allergic reaction:

  • Always read ingredient labels before buying or consuming a product. Avoid products that don't list all ingredients and those whose labels you don't understand. 
  • Avoid cross-contamination, in which a small amount of mustard accidentally gets into your food. This might happen when someone preparing food with mustard uses the same utensil to prepare or serve food to a person with mustard allergies.
  • Before eating with friends, tell them about your allergy so they’ll know what to do in the event of an emergency.
  • While eating out, always ask whether the restaurant uses mustard to prepare what you’re ordering. Tell anyone handling your food to avoid using mustard or any ingredients that may contain it. 
  • Consider eating out when a restaurant is less busy to avoid cross-contamination.
  • Beware of salad bars and buffets. Many salads contain hidden mustard. And you run the risk that the same serving utensil was used in different dishes.
  • Educate yourself (or your child, if they have allergies) on how to handle allergic attacks.