Thai chillies, phrik khi nu in Thai, are small, slender and very hot – Thai cooking would be unthinkable without them. The name literally means “mouse droppings”.

| Species | Capsicum annuum and C. frutescens – the name covers small hot chillies of both species |
|---|---|
| Heat | 50,000–100,000 SHU (University of Florida); Thai cultivars mostly 45,000–80,000 SHU |
| Thai name | phrik khi nu (พริกขี้หนู), literally “mouse droppings” |
| Fruit | small and slender, green when unripe, red when ripe |
| Uses | curry pastes, stir-fries, soups, salads, nam phrik dips |
Which species?
Sources disagree. The University of Florida classifies the Thai pepper as C. annuum and notes it is often confused with C. frutescens cultivars, while a 2021 Thai study places phrik khi nu in C. frutescens. Another Thai study (2008) of ten Thai chilli cultivars found six C. annuum and four C. frutescens. It is most accurate to say that in Thailand the name covers small hot chillies of both species.
Heat
The University of Florida gives 50,000–100,000 SHU – more than cayenne or Tabasco. The 2008 Thai study measured most cultivars at 45,000–80,000 SHU, with Huarua and K07 above 80,000 SHU. According to food writer Austin Bush, phrik khi nu are generally the hottest chillies in Thailand.
In Thai cooking
Bush writes that phrik khi nu are pounded into curry pastes, crushed into stir-fries, soups and salads, and used in nam phrik dips; dried ones go into curry pastes. In 2021 Thai scientists also used them to make nam phrik phao chilli paste and red curry paste.
Related
Tabasco · Cayenne · Peperoncino · Scoville scale
Sources
- UF/IFAS Gardening Solutions: Peppers by Scoville units
- Korarnan et al. (2021). Journal of Science Ladkrabang 30(2). article
- Kasetsart Journal (Natural Science) 42: 611–616 (2008). article
- Bush A.: Phrik 101: Thai chili primer