Celery is a green vegetable whose leaf stalks are commonly used in cooking. It has a high water content and a subtle, almost bitter taste that serves as a unique flavor base in many recipes. Celery is often used in soups and stews, alongside garlic to build up flavor. The fibers in celery stalks also add a bit of crunch to dishes. Celery seeds are used as a dried spice and adds great flavor to dishes such as macaroni or potato salad. Celery is rich in vitamin K, vitamin A, calcium and potassium.