Rasam is a South Indian soup made with a base of tamarind juice and added ingredients such as pepper, cumin, chili, lemon, lentils, and tomatoes, resulting in a tangy and sour flavor of the dish. The name of the dish can be literally translated to juice, referring to tomato or tamarind juices.

Originally, rasam was made only with tamarind and black pepper due to the abundance of those ingredients in South India. The soup is usually served as an appetizer with rice on the side. Traditionally, it is consumed after sambar, and followed by the main dish with curd rice.

Over time, the popularity of rasam helped in the creation of mulligatawny soup as rasam's Anglo-Indian version. There are numerous regional varieties of rasam throughout South India, such as nellikkai rasam with Indian gooseberries, inji rasam with ginger, and vepam poo rasam with neem flowers.