(FORTUNE Small Business) – Doug Lambrecht is on a mission: to convince diners of the benefits of real wasabi. Most sushi restaurants, both in the U.S. and Japan, do not serve the genuine article. That green stuff next to your spicy tuna roll is usually a combination of horseradish, mustard extract, and food coloring. Genuine wasabi is expensive (the plants are hard to cultivate) and tastes sweeter, with less concentrated heat. Lambrecht's company, Real Wasabi, based in Hilton Head, S.C., which he launched with two partners a year ago, aims to spread the green truth.

An independent investment advisor, Lambrecht, 54, has always loved wasabi, to the point where he once put a WASABI vanity plate on his green BMW. After tasting the real thing seven years ago, he started researching the plant's putative health benefits. Wasabi has antibacterial qualities (which is why Japanese chefs first paired it with raw fish--to protect diners from microbes if the fish had gone bad), and some holistic health experts claim that it strengthens the immune system, reduces mucus, fights cancer, and detoxifies the liver and digestive system.

Lambrecht launched Real Wasabi in January 2005 with two entrepreneur buddies: Brooks Quinn, 43, a landscape architect and ex-restaurateur; and Mike Tousey, 50, founder of DI Pharma Tech, which helps drug companies manufacture tablets and capsules. Real Wasabi imports wasabi plants from Asia, which it then dries, grinds, and blends into a powder. (Lambrecht hopes to grow them on the East Coast someday, and early field tests in the streambeds of his 75-acre farm in Cashiers, N.C., have been somewhat promising.) You reconstitute the powder by adding water and letting the mixture sit for ten minutes. Real Wasabi sells the powder online--$5.95 for half an ounce--along with six wasabi-based salad dressings and sauces. The company is lining up distribution deals with health-food stores and grocers.

A West Coast competitor, Pacific Farms, based in Florence, Ore., has grown wasabi plants and sold wasabi paste since 1997. Ted Wakeman, head of farm operations at Pacific Farms, says he welcomes the new competition: "Anyone selling a real wasabi product is educating the public, and that is good for us."

Lambrecht says he loves working with a product that is authentic and palate-pleasing, but he also sees a business opportunity. "I am an unapologetic capitalist," he says. "I expect to make money."