Wasabi (Japanese: 山葵) is a fiery green seasoning paste made in Japan from the rhizome of the Eutrema japanicum plant, as well as the name of the plant itself. The heat of wasabi is similar to that of horseradish and mustard, rather than chili peppers.
The plant is difficult to cultivate, so most "wasabi" encountered commercially is actually made with colored horseradish. This product is known as "Western wasabi", 西洋山葵, in Japan.