How to Introduce Common Allergens Safely
Updated 7 October 2026
Earlier is generally better, not later
Guidance has shifted over the last decade: deliberately delaying common allergens doesn't reduce the risk of allergy, and for foods like peanut and egg, introducing them from around 6 months (once your baby is ready for solids at all) is now the general recommendation, rather than avoiding them out of caution.
The six foods to introduce deliberately
Most food allergies in babies come from a small group: peanut, egg, cow's milk (dairy), wheat, fish, and sesame. These are worth introducing one at a time and paying attention to, rather than mixing several new allergens into one meal.
How to introduce one
- Offer a small amount the first time — a teaspoon-sized taste, not a full portion.
- Do it earlier in the day, so you have time to notice a reaction rather than it happening overnight.
- Don't introduce it alongside another new allergen in the same meal — if there's a reaction, you want to know which food caused it.
- If there's no reaction, offer it again, gradually increase the amount, then keep it as a regular part of their diet — occasional, one-off exposure is less useful than continuing to offer it.
What a reaction can look like
Most reactions are mild: a rash around the mouth, mild hives, or an upset stomach. Watch for these and stop the food if they appear. Seek urgent medical help if you notice swelling of the lips, face, or eyes, difficulty breathing, persistent vomiting, or your baby seems suddenly very unwell — these need emergency attention, not a wait-and-see approach.
If your family has a history of allergies
If your baby has severe eczema, an existing food allergy, or a parent/sibling with a food allergy, talk to your health visitor or GP before introducing these foods — they may suggest doing it under medical guidance rather than at home first.
