Chilli is an erect, branched, shrub-like herb with fruits used as garnishing and flavouring in Thai dishes. There are many different species. Red chillies: These are fatter and less spicy, often sliced and used in Thai curry and soups. These chillies are hotter than jalapeÃ±os. Though much-maligned for imparting a hotness that can be unbearable and lasting, red chillies used in conjunction with other spices can add zing to any boring dish.