Rasam (Tamil: ரசம், Rasam, Malayalam: രസം), Kannada:ಸಾರು (Saaru), is a South Indian soup, traditionally prepared using tamarind juice as a base, with the addition of tomato, and chili pepper, pepper, cumin and other spices as seasonings. Steamed lentils are added along with any preferred vegetables. Nowadays all the seasonings required are combined and ground beforehand into a rasam powder, which is available commercially.

It is eaten with rice or separately as soup. In a traditional meal, it is preceded by a sambar rice course and is followed by curd rice. Rasam has a distinct taste in comparison to the sambar due to its own seasoning ingredients and is usually fluid in consistency.

In Sanskrit language, 'Rasa' means Juice. It can refer to any juice but in Tamil simply rasam commonly referred to the one prepared with Tamarind/Tomato juice with added spices. Saaru (ಸಾರು) in Kannada language or Chaaru (చారు), in Telugu language, means "essence," and, by extension, "juice" or "soup". Historically, it was prepared mainly with black pepper and tamarind, both ingredients native to and abundant in South India in general. It is also referred to as SatruAmudhu (Tamil: சாற்றமுது) by Iyengars.