Hippocrates, the ancient Greek physician who said “let food be thy medicine,” so believed in the healing powers of watercress that he built his first hospital next to a stream so he could grow it. The Romans and Anglo-Saxons believed watercress averted baldness and Francis Bacon, a 17th-century English philosopher and politician, said it would restore women’s youth. Watercress’s Latin name, Nasturtium officinale, means “nose twister”—an appropriate description considering its pungent, peppery taste. Isothiocyanates—antioxidants that amp up your body’s detoxifying enzymes—give watercress its distinctive bite. Studies suggest these compounds may even help prevent cancer and lower cholesterol. A longstanding British favorite in tea sandwiches, watercress is actually quite versatile: use it in a soup or as part of a green salad.