Red chilies are a central ingredient in Thai cuisine, but Thai cooks also use green and yellow chilies, hence the three famous colors of Thai curry: green curry, red curry and yellow curry. Each Thai dish is usually made with a certain chili, although you can always easily substitute red chili if you can't find green or yellow. Characteristic of the Thai sense of humor, the hottest of these chilies, called phrik kii noo, literally means “mouse droppings”, but they're also popularly known as 'bird's eye chilies' , simply because looking at one from the stem-end can appear like the eye of a bird.