Narthangai is a traditional citrus fruit widely used in Tamil Nadu cuisine and Siddha/Ayurvedic practices. The fruit is large, oval to oblong, with a very thick, rough yellow rind when mature. The pulp inside is less juicy and mildly sour, while the rind is highly aromatic.

Narthangai is best known for making Narthangai oorugai (pickle), candies, and preserved products. It is also valued for its digestive benefits and refreshing aroma.

The plant is a small evergreen tree or shrub, suitable for warm tropical climates, requiring good sunlight and well-drained soil. Fruits are usually harvested during the winter to early summer season.