How to Introduce Peanut, Egg, and Dairy to Your Baby Safely

Most babies are ready for allergen foods around the same time they start solids — typically around 6 months, and never before 4 months. Your baby should be sitting with support, showing interest in food, and able to move food to the back of the mouth and swallow.

Run through this checklist before the first try:

• Your baby is healthy — no cold, fever, vomiting, or diarrhea that day.
• It's a weekday morning, so you have a full day of watching and easy access to your doctor if needed.
• Someone can stay with your baby for at least 2 hours after the feed. Reactions usually show up within minutes to a couple of hours.
• You know where your nearest emergency care is and how you'd get there.
• If your baby has severe eczema or a known food allergy in the family, talk to your pediatrician first — you may be told to introduce allergens earlier or under supervision.
• Have your phone charged and your baby's health records handy.

One food at a time, one allergen at a time. Don't start two new allergens on the same day — you won't know which one caused a reaction.

The 3-Day Rule: How to Space New Foods and Track Reactions

When you start allergens, introduce only one new allergen at a time. Wait about three days before trying the next one. This gives you a clear window to spot delayed reactions, like a rash or an upset stomach, which can show up hours or even a day or two later.

Here is how to run the 3-day window:

1. Day 1: Offer a small amount of the new allergen in the morning, not at bedtime. If a reaction happens, you want daylight and an awake baby.
2. Days 2–3: Repeat the same food in a slightly larger amount, once or twice a day.
3. Days 4–5: If all is well, move on to the next allergen — or keep rotating the foods your baby has already tolerated.

Keep a simple food log. Write down the food, the time, the amount, and anything unusual: a red patch around the mouth, extra spit-up, loose stools, or unusual fussiness. A notes app works fine.

One exception: you do not need to space out familiar foods your baby has already eaten many times. The 3-day rule applies to new allergens only. Once a food has been tolerated, keep serving it regularly — roughly a couple of times a week — to maintain tolerance.

Introducing Peanut: Step-by-Step From Thin Paste to Regular Servings

Peanut is one of the most common allergens, so introduce it deliberately. Never give whole peanuts or chunky peanut butter — both are choking hazards. Use smooth peanut butter, thinned, or peanut flour mixed into a purée.

1. Mix about 2 teaspoons of smooth peanut butter with 2–3 teaspoons of warm water, breast milk, or formula until it's a thin, runny paste.
2. Offer a tiny taste — a quarter of a teaspoon — on a spoon.
3. Wait 10–15 minutes and watch for hives, swelling, vomiting, or fussiness beyond normal.
4. If all is well, offer the rest of the serving.

If there's no reaction, keep offering peanut two to three times a week. Regular exposure matters more than the first taste — an allergen introduced once and then dropped doesn't build tolerance. Aim for roughly 2 grams of peanut protein per serving, which is about 2 teaspoons of peanut butter.

Easy serving ideas: stir thinned peanut butter into oatmeal or yogurt, or spread it thinly on toast strips cut into narrow pieces. If your baby has severe eczema or a known egg allergy, check with your doctor before the first taste.

Introducing Egg: Starting With Well-Cooked Before Runny Yolks

Egg is a common allergen, so introduce it deliberately. Start with egg that is thoroughly cooked — hard-boiled yolk, scrambled egg cooked until firm, or egg baked into a pancake. Well-cooked egg is easier to tolerate than runny yolk, so save that for later.

1. Hard-boil an egg. Mash a small amount of the yolk with a little breast milk, formula, or water to make a soft paste.
2. Offer about a quarter of a teaspoon. Wait and watch as you would with any new food.
3. If there is no reaction, offer a little more the same day, then stop.
4. Repeat the same food over the next couple of days before moving on.

Once well-cooked egg is tolerated regularly, you can move to softer textures: omelette strips, then scrambled egg. Runny or lightly cooked yolk can come later, typically after well-cooked egg has been accepted for several weeks. Always serve eggs cooked through at first — raw or undercooked egg carries a food safety risk as well as an allergy risk.

Keep portions small at the start. A few spoonfuls count as an exposure; regular servings matter more than big ones.

Introducing Dairy: Yogurt and Cheese First, Cow's Milk as a Drink Later

Dairy is one of the easier allergens to introduce because most babies already enjoy the texture of yogurt and cheese. Start with full-fat, plain products rather than low-fat versions — babies need the fat for energy.

1. Offer a small amount of plain whole-milk yogurt, about a teaspoon, at breakfast or lunch.
2. Watch your baby for the rest of the day, following the 3-day rule before adding another new allergen.
3. If all is well, increase to a few tablespoons over the next week or so.
4. Add cheese next. Grate a mild, pasteurized cheese like mozzarella and offer a small pinch, softened on a spoon or melted into vegetables.

Hold off on cow's milk as a main drink until roughly the first birthday. Before that, milk in food — mixed into porridge, yogurt, or sauces — is fine. As a drink, it can crowd out breast milk or formula and doesn't contain the iron babies still need in their first year.

Avoid unpasteurized (raw) milk products entirely, and skip soft cheeses made from raw milk. Once dairy is tolerated, keep serving it regularly — a few times a week at minimum — to maintain tolerance.

What a Reaction Looks Like and What to Do in the First 10 Minutes

Most mild reactions show up within minutes to about two hours of eating. Learn the signs before you need them.

Mild signs: a few hives, redness around the mouth, or a single patch of itchy skin. Stop feeding, wipe the area, and give an age-appropriate antihistamine if your pediatrician has approved one in advance.

Serious signs — act immediately:

• Swelling of the lips, tongue, or throat
• Repeated vomiting
• Wheezing, persistent coughing, or noisy breathing
• Unusual floppiness, pallor, or drowsiness

First 10 minutes:

1. Stop feeding and stay with your baby.
2. Call emergency services for any breathing trouble, throat swelling, or repeated vomiting.
3. If an epinephrine auto-injector has been prescribed, use it as directed, then call emergency services anyway.
4. Do not drive yourself if breathing is affected — wait for help.

Log every reaction, even mild ones, with the food, amount, and timing, and share it with your pediatrician before the next attempt. A mild skin reaction usually means retrying later with medical guidance, not never trying again.