Allergic reactions to spices are rare and usually mild, but occasionally people who are sensitive to a certain spice can have a severe reaction.
Some people react to mustard, coriander, caraway, fennel, paprika or saffron and, less frequently, to onions, garlic or chives. Reactions to mustard can cause anaphylaxis. Mustard allergy is more common in countries in mainland Europe, where mustard is used more than in the UK. See the section on mustard allergy.
The allergens in spices are similar to those in pollens and vegetables, and people who are allergic to mugwort and birch pollen are more likely to be sensitive to spices for this reason.