Rather tart and astringent in taste, sumac ( or sumak) is often referred to as a "souring agent." It was once used to calm the stomach. Today sumac is considered mainly a condiment used much like salt in that it is passed in small dishes at the table. The spice is tasty on grilled meats and fish or as a seasoning for rice. It complements lentils and other beans as well as vegetables. "Try seasoning a thinly sliced onion with 2 tsp. of sumac,white beans and olive oil" serve cold :) Great salad with any dish but esp. with sea food.