The Heat Is Not the Same at Every Stall and That Is the Whole Trick
Thailand's chillies run from a mild, floral heat to something that genuinely hurts. Knowing which pepper is on your plate turns every meal from a gamble into a decision.
The first thing anybody tells you about Thai food is that it is spicy. The second thing, which is more useful, is that the word phet on a menu is not a measurement. It is a claim, and the claim is made by a restaurant that has never met you.
So you learn the peppers instead.
Last verified 1 August 2026.
There are three chillies that matter
Prik kee is the green one, and it is the mildest of the three, with a grassy, fresh heat rather than a burning one. It is what most of a green curry actually is, and green curry is not the aggressive dish people think it is.
Prik chi fah is the small, round, deep red one that appears in almost everything stir-fried, and it brings a slow, clean, spreading heat with a little fruit in it. This is the default Thai chilli and the reason a stir-fry can be more fiery than a curry.
Prik ha is the big pale one that looks mild and is not. Fresh green or ripe red, it is the chilli that sits in a Tom yum and in a green curry and does not announce itself until about four seconds after you swallow.
Dried chillies are a different ingredient. Prik haet, the dried version, is used in curries and has a deeper, rounder heat than the fresh thing, and it is the reason a curry can be building slowly while your mouth says nothing is happening yet.
What nam phet prik means
The literal translation is literally hot. Nothing in the phrase tells you whether that means a pleasant warmth or an argument.
But in practice, on a menu, nam phet prik is used loosely, the way a menu in any country uses chilli rating. A dish described that way is a dish the cook expects people to find exciting rather than dangerous.
The tell is elsewhere on the menu. If a place lists six dishes and two of them are nam phet prik, those two are their idea of their boldest food. That is a very different situation from a menu where all eight are marked the same way, which usually means the kitchen is not interested in nuance.
How to ask for less heat, properly
Mai phet, khrap is the phrase, and it is enough for most situations. The polite particle at the end is worth keeping. It is a request rather than an instruction.
Mai phet jai means not spicy to the stomach, and this is the one that works better than mai phet alone, because it asks for the kitchen to build the dish around the absence of heat rather than to add a pile of sugar on the end.
What you will usually get is a milder version of the same dish, with the chillies left out at the cooking stage rather than fished out afterwards. A few places will serve you the whole bowl and a saucer of nam prik on the side so you can add it yourself, which is the ideal arrangement and worth asking for explicitly.
Ask early. Requesting a mild version after the food has arrived is a different conversation, and the result is usually a bowl of plain rice.
Heat is not a single axis
There is a difference between heat you can eat through and heat that is trying to remove you. Fresh prik kee is the first kind. A large quantity of dried prik haet is the second. They sit in completely different cuisines.
There is also a difference between heat and numbing. That is a different ingredient entirely, and it is not a chilli. If something makes your lips feel strange, that is not heat and asking for less of it will not help.
And there is a difference between heat and a lot of salt and fish sauce, which is the honest reason a lot of people who claim not to like spicy food do not like Thai food. If the real problem is nam pla, ask for jam nam pla, less fish sauce, and leave the chilli alone.
What to drink, which matters more than people expect
Water is fine and the one thing you should always have. Sugary soft drinks and Thai iced tea make the heat worse, not better, because you are adding sugar to a system that is already sending messages to your brain about temperature.
Milk is a genuinely effective reset, because capsaicin is fat soluble and dairy carries it away. If there is one thing to eat when a Tom yum has gone wrong, it is not water, it is a spoon of khom tao rice pudding or a spoon of coconut milk if it is on the table.
And do not be brave. The local order of a bowl in front of you is not a challenge. Nobody is watching, nobody is keeping score, and the only person who suffers if you eat the whole thing is you, on a night bus, three hours later.
