The Big 9 allergens schedule (day-by-day)

Check your baby's developmental readiness for solids first — use our free milestone tracker to confirm the four key signs.

Why early introduction matters

Old advice told parents to delay top allergens until age 1, 2, or even 3. New research (most famously the LEAP study on peanuts) flipped this entirely. Delaying introduction increases the risk of food allergy. Early, regular exposure trains the immune system to tolerate proteins instead of treating them as threats.

The American Academy of Pediatrics, the National Institute of Allergy and Infectious Diseases, and most international pediatric associations now recommend introducing all top allergens between 4 and 11 months, ideally starting at the same time as other solids, with continued exposure several times a week.

The Big 9 — what's on the list

1. Peanut
2. Egg
3. Cow's milk (dairy)
4. Wheat
5. Soy
6. Sesame
7. Fish (cod, salmon, tilapia)
8. Shellfish (shrimp, crab)
9. Tree nuts (almond, cashew, walnut)

The FDA added sesame to the "major allergen" list in 2023, replacing the older "Top 8" with the Big 9.

Before you start — the readiness checklist

• Baby is at least 4 months old (some allergists prefer 6 months; align with your pediatrician).
• Baby has sustained head and neck control.
• Baby can sit upright with minimal support.
• Baby is showing interest in food (watching you eat, leaning in).
• Tongue-thrust reflex is fading.
• Baby is well — not fighting a virus, not just vaccinated within 24 hours.

The rules that apply to every allergen

• Introduce one new allergen at a time. Wait 2 to 3 days before introducing the next one.
• Offer in the morning, ideally after a milk feed so baby isn't ravenous. You want plenty of awake daylight hours to watch for delayed reactions.
• Start small. A pea-sized amount on the first try, increasing over 2 to 3 exposures within the same week.
• Stay at home for the first introduction of each allergen. Have a phone with Poison Control and your pediatrician's number nearby.
• Continue exposure after introduction. 2 to 3 times per week, ongoing. Allergy prevention requires regular exposure, not a one-time taste.

The 9-week day-by-day plan

Week 1 — Peanut

Peanut first because it's the most studied and most common severe allergen. Use smooth peanut butter (never whole peanuts, never crunchy — choking risk) thinned with breast milk, formula, or warm water to a runny consistency. Mix into oatmeal or offer on a spoon.

• Day 1 (Monday): 1/8 teaspoon thinned peanut butter. Watch for 2 hours.
• Day 3 (Wednesday): 1/4 teaspoon.
• Day 5 (Friday): 1/2 teaspoon.
• Maintenance: 2 grams of peanut protein, 3 times per week (roughly 1 to 2 teaspoons of peanut butter spread thinly).

Week 2 — Egg

Cooked egg only. Scrambled, hard-boiled (mashed), or baked in a muffin. No raw egg, no soft-cooked yolk.

• Day 1: 1/8 teaspoon scrambled egg.
• Day 3: 1/4 of a scrambled egg.
• Day 5: 1/2 of a scrambled egg or a small egg-based muffin.
• Maintenance: Egg 3 times per week. Can be a small piece of frittata, scrambled egg, egg-bread, or french toast.

Week 3 — Cow's milk

Not as a drink (wait until 12 months for whole milk as a beverage). As yogurt, cheese, or mixed into food.

• Day 1: 1 teaspoon full-fat plain yogurt.
• Day 3: 1 tablespoon yogurt.
• Day 5: A small cube of soft cheese or 2 tablespoons of yogurt.
• Maintenance: Yogurt or cheese 3+ times per week.

Week 4 — Wheat

Iron-fortified baby wheat cereal, small pieces of soft bread, or pasta.

• Day 1: 1 tablespoon prepared baby wheat cereal.
• Day 3: 2 tablespoons cereal or a finger of soft toast.
• Day 5: Small piece of pasta or pancake.
• Maintenance: Wheat at most meals — easy to incorporate.

Week 5 — Soy

Tofu (silken or firm, cubed small), edamame mashed, or soy yogurt. Soy sauce is too salty for babies under 1.

• Day 1: 1 teaspoon mashed silken tofu.
• Day 3: 1 tablespoon tofu.
• Day 5: A small finger of firm tofu or 2 tablespoons of mashed edamame.
• Maintenance: 1 to 2 times per week.

Week 6 — Sesame

Tahini (sesame paste) thinned with water or mixed into hummus. Tahini is the safest form because sesame seeds themselves are a choking hazard for babies.

• Day 1: 1/8 teaspoon tahini thinned in oatmeal.
• Day 3: 1/4 teaspoon tahini, or a teaspoon of hummus on a finger of toast.
• Day 5: 1/2 teaspoon tahini or a tablespoon of hummus.
• Maintenance: Hummus or tahini 2 times per week.

Week 7 — Fish

White fish first (cod, tilapia) is mildest. Salmon next. Always check carefully for bones. Avoid high-mercury fish (tuna, swordfish, king mackerel) under age 2.

• Day 1: 1 teaspoon flaked cooked cod, bones removed, on the back of a spoon.
• Day 3: 1 tablespoon flaked white fish.
• Day 5: 1 tablespoon flaked salmon.
• Maintenance: Fish 1 to 2 times per week.

Week 8 — Shellfish

Shrimp is most common. Use fully cooked, finely chopped (or pureed for younger babies).

• Day 1: 1 teaspoon finely chopped cooked shrimp mixed into rice or pasta.
• Day 3: 1 tablespoon shrimp.
• Day 5: 2 tablespoons shrimp.
• Maintenance: Shellfish 1 time per week if family eats it.

Week 9 — Tree nuts

Use smooth nut butter (almond, cashew, walnut) thinned with breast milk, formula, or water. Whole tree nuts and chunks of nut butter are choking hazards under age 4.

• Day 1: 1/8 teaspoon thinned almond butter.
• Day 3: 1/4 teaspoon almond butter, then try cashew butter on day 5.
• Day 5: Cashew butter thinned, 1/4 teaspoon.
• Maintenance: Tree nut butter 2 to 3 times per week, rotating types.

How to spot a reaction

Mild reactions (within 2 hours):

• Hives or a localized rash where food touched.
• A few hives elsewhere.
• Itchy mouth.
• Mild vomiting or diarrhea.

For mild reactions: stop offering that food. Call your pediatrician. Get an allergist referral.

Severe reactions (anaphylaxis — within minutes to 2 hours):

• Swelling of lips, tongue, face.
• Difficulty breathing, wheezing, or noisy breathing.
• Hives all over the body.
• Vomiting paired with breathing or skin changes.
• Pale skin, sudden floppiness, loss of consciousness.

For severe reactions: call 911 immediately. If you have an EpiPen, use it (most parents don't until after the first severe reaction — that's the moment your pediatrician should be involved in next steps).

If your baby has eczema or a sibling with allergy

Talk to your pediatrician before starting the allergen plan. Babies with moderate-to-severe eczema or a sibling with a food allergy are at higher risk and may benefit from allergy testing before introduction, or a controlled introduction in a doctor's office. Don't skip allergens because of this — delaying makes it worse. Coordinate.

When to call your pediatrician

• Any reaction, even mild — get advice on continuing or holding off.
• Persistent rash, eczema flare, or GI symptoms (especially mucus or blood in stool) after introducing a food.
• Your baby has known allergies in siblings.
• You're unsure how to proceed safely.