Tamarind sauce is a critical ingredient in many Thai foods, including the famous Pad Thai. Tamarind sauce is commonly used in various northern Thai dishes as a souring agent. Tamarind is also used in the manufacturing of ketchups, sauces--Chinese, Worcestershire, Barbecue, etc. Tamarind is also very effective as a natural preservative and marinade. Usually tamarind paste is mixed with water and strained, the resulting tamarind juice being what's used. This product is a concentrated form of tamarind juice (and very convenient to use because it removes the need for mixing & straining).