Ajwain seeds are used as a spice. The grayish-green seeds are striped and curved (similar to cumin or caraway seeds in appearance), often with a fine silk stalk attached. They are usually sold whole. The seeds are often chewed on their own for medicinal value, tasting bitingly hot and bitter, leaving the tongue numb for a while. Cooking ajowan mellows it somewhat. When crushed, they have a strong and distinctive thyme-like fragrance