Basil
A pungent herb much used in the Mediterranean regions and in South East Asia. Three varieties of basil are used in Thai cooking - bai kaprow (Holy or purple basil), bai horapa (sweet basil), and bai mangluk (lemon or hairy basil),

Holy basil (bai kaprow)
Holy basil has a hot flavor and slightly medicinal. It has a purple stem and purple leaves, usually used in stir-fried menu such as Stir-Fried Chicken with holy basil leaves (Pad Krapao Gai).