Sium suave (from the Latin sium, the Latinization of Greek sion, meaning "water parsley," and suâvis, meaning "sweet."), the hemlock waterparsnip or water parsnip, is a herb native to parts of Eurasia and North America.

The water parsnip is a member of the Apiaceae family and appears with leaves and white flowers during blooming. The plant lives in marshes and other wetland in areas below 3000 feet.