Originally published March 2018. Reviewed and substantially corrected August 2026 to reflect current NIAID, AAP and AAAAI guidance.
Nobody has time to sort through the constantly changing, conflicting advice on infant feeding — and Google makes it worse, not better. So here is the current version, plainly.
The old advice was backwards
For years parents were told to delay allergenic foods as long as possible. That advice has been reversed. There is no evidence that waiting past 4–6 months prevents food allergy, and for peanut specifically, early introduction actively reduces the risk of developing an allergy.
That finding came from a landmark trial and changed national guidance. It is the single most useful thing on this page.
The foods that actually matter
The original version of this article listed “cow’s milk, eggs, tree nuts and strawberries.” That was wrong, and we want to correct it clearly. Strawberries are not a major allergen — they can cause a harmless rash around a baby’s mouth, which is probably where the folk belief comes from, but that is not a food allergy. And the list left out peanut, which is the most important one of all.
The nine major food allergens in the United States are:
- Milk
- Egg
- Peanut
- Tree nuts
- Soy
- Wheat
- Fish
- Shellfish
- Sesame — added as the ninth in January 2023, after this article was first written
When to introduce them
For most babies: start solids around 6 months (not before 4 months), and introduce allergenic foods along with everything else. There is no reason to save them for later.
For babies at higher risk, peanut is different and timing matters. If your baby has severe eczema, an egg allergy, or both, current guidance is to introduce peanut earlier — in the 4-to-6-month window — and to have your baby evaluated first. That evaluation exists to make earlier introduction safe, not to justify waiting.
This is the part the earlier version of this article got wrong. It told every parent to wait until six months, which for a high-risk baby delays exactly the intervention that helps most. If your baby has significant eczema or a known egg allergy, please talk to us before you introduce peanut — don’t just follow a blog post, including this one.
How to do it
- Start with single-ingredient foods, plain, with nothing added.
- Introduce one new food every 3 to 5 days, watching in between. (The earlier version said one a day. That’s too fast to tell which food caused a reaction — and it contradicted its own point that reactions can be delayed by hours.)
- Never give whole peanuts or nuts to an infant or toddler — they are a serious choking hazard. Use smooth peanut butter thinned with water or mixed into puree, or a peanut puff that dissolves.
- Keep it in the diet. This is the step people miss: introducing an allergen once isn’t enough. Regular, ongoing exposure is what maintains tolerance. A food introduced at six months and then not offered again for a year hasn’t done its job.
- Introduce at home during the day, when you can watch your baby and reach us if needed — not at bedtime or in the car.
About cow’s milk — two different things
These get confused constantly, and the earlier version of this article didn’t separate them:
- Cow’s milk as a drink: wait until after the first birthday. Breast milk or formula remains the main drink for the first year.
- Dairy foods like yogurt and cheese: these can be introduced with other solids. They count as allergen exposure and there is no reason to hold them back.
What a reaction looks like
Most reactions begin within minutes to a couple of hours: hives, swelling around the lips or eyes, vomiting, or a sudden rash. Call 911 for trouble breathing, swelling of the tongue or throat, repeated vomiting with paleness or floppiness, or collapse. For milder symptoms, call us — and stop that food until you’ve talked to someone.
Talk to us first if…
Your baby has severe or hard-to-control eczema, a known food allergy, or a sibling or parent with significant food allergy. Those situations deserve a plan rather than a guess. Call (417) 332-3639 and we’ll work it out with you — often that means introducing sooner rather than later, with the right precautions.
One less thing to research. Check.
Carolyn Clark, NP-C
General education, not medical advice for your child. Infant allergen introduction is risk-stratified — if your baby has eczema or a known allergy, get individual guidance before you start.