Eating Thai food with a food allergy: peanuts, shellfish and hidden seasonings

People with food allergies watch for what they can see: peanuts on pad thai, prawns in tom yum. In Thai food, though, many allergens hide in seasonings prepared in advance: shrimp paste in curry pastes, oyster sauce in stir-fries, or a mortar that just pounded a peanut-and-dried-shrimp som tam for the previous customer. This article covers where things hide, what to ask, and how to say it so the kitchen understands.

This is general information, not medical advice. If your allergy is severe, talk to your doctor before eating out and follow the plan they give you. Recipes differ between kitchens, so ask every time.

What hides in the seasonings

Allergen	Obvious in	Hidden in
Shrimp and crustaceans	Tom yum goong, prawn stir-fries	Shrimp paste (kapi) in almost every curry paste; dried shrimp in som tam, pad thai, chili dips, chili jam
Molluscs	Fried mussels, stir-fried clams	Oyster sauce in many stir-fries
Fish	Fried fish, fish curry	Fish sauce in nearly every dish; pla ra, budu, tai pla
Peanuts	Peanuts on pad thai	Thai-style som tam, massaman curry, satay sauce, some salads, some Thai sweets
Wheat (gluten)	Noodles, batter	Soy sauce, seasoning sauce, oyster sauce: many brands contain wheat
Egg	Fried egg, omelette	Pad thai, fried rice, egg noodles, some batters
Soy	Tofu	Soy sauce, tao jiao (fermented soybean paste), the dipping sauce for khao man gai
Milk	Thai iced tea, desserts	Creamy tom yum at some places; coffee and tea with condensed milk

The top two rows matter most in Thai food, because shrimp paste is a base ingredient of most curry pastes: green curry, red curry, gaeng som and southern pastes. Anyone allergic to shrimp should ask about every curry, even when the menu name says nothing about shrimp.

Shared equipment

Many Thai kitchens cook everything with one set of tools all day.

• The som tam mortar is used order after order. One that just pounded peanuts and dried shrimp may hold traces. If you are allergic, ask for it to be washed first.
• The made-to-order wok cooks dish after dish; some stalls only rinse it with water in between.
• Frying oil in one pot may fry prawns, fish and battered food.
• Ladles and broth at a noodle stall: one pot of broth blanches fish balls, prawns and every kind of noodle.

If even small traces cause a reaction, this matters as much as the ingredients.

Three questions to ask

Before ordering a dish you are unsure of, ask about:

1. Ingredients: does this dish have …?
2. Seasonings: does the sauce, chili dip or curry paste have …?
3. Equipment: was the mortar or wok just used with …? Could you wash it first?

If the answer is unclear, or the stall is too busy to answer, choose a dish with no risk in the first place. It is simpler and safer.

Example: allergic to peanuts and shrimp, craving som tam

Step	What you find	What you do
1 Check the recipe	Tam Thai has peanuts and dried shrimp	Ask for neither
2 Check the seasonings	Fish sauce is not shrimp; pla ra is not shrimp	Ask whether they add shrimp paste or ground dried shrimp to the dressing
3 Check the equipment	One mortar, used all day	Ask them to wash it before pounding
4 Decide	The stall is busy and cannot wash it	Order grilled chicken and sticky rice instead

The example shows that “no peanuts, no shrimp” is not enough on its own. You need two more steps, and sometimes the safest answer is a different dish.

What to tell the kitchen

Always say “allergic” (phae, แพ้) and how serious it is.

• “แพ้ถั่วลิสง กินไม่ได้เลยแม้นิดเดียว” — I am allergic to peanuts, I cannot have even a little.
• “แพ้กุ้ง รวมถึงกะปิและกุ้งแห้งด้วย” — I am allergic to shrimp, including shrimp paste and dried shrimp.
• “จานนี้มีกะปิหรือซอสหอยนางรมไหม” — Does this dish have shrimp paste or oyster sauce?
• “ช่วยล้างครกก่อนตำได้ไหม” — Could you wash the mortar before pounding?

If you do not speak Thai, write these on a card or keep them on your phone and show them to the cook. That is clearer than shouting over a busy kitchen.

Say “allergic”, not “I do not like it”. And if you are unsure, change the dish.

Common mistakes

• Reading only the menu name. Green curry with chicken says nothing about shrimp, but the paste usually has shrimp paste.
• Assuming soy sauce is wheat-free. Many soy and seasoning sauces are brewed with wheat. If you avoid gluten, read the label or ask.
• Letting a friend order for you without saying anything. Confirm the allergy with the kitchen yourself.

Summary

You can enjoy Thai food with a food allergy, as long as you know that allergens often hide in seasonings and equipment rather than on the plate. Ask about ingredients, seasonings and equipment, say “allergic” clearly, and when in doubt, change the dish. With a severe allergy, talk to your doctor first, and know that the emergency medical number in Thailand is 1669.