For argument's sake, a genie rises over Dr. Sidney Wolfe's grubby green metal desk in these ancient, ultra-Nader, worn-linoleum offices over Dupont Circle.

Wolfe, who heads Nader's Health Research Group, listens to how this hypothetical genie wipes out all the red dye No. 2, the vinyl chloride, the unnecessary surgery, the DES, the additives, the Darvon, all the things that go bump in this latter-day ecological night.

He smiles. He fingers a green-and-gold paisley necktie that looks like he's fingered it before. He listens to that wise-guy question everybody wants to ask of high-profile public-interest types: If the genie were to solve all problems, how would he fill that 55-hour work week?

"I would sit that genie down," Wolfe announces, with a giggle fidgeting at the back of his nose, "and I would interview him for months and months to find out how the... he did it!"

Technique: Nader may have pioneered the practice of public interest law, but Wolfe, at 41, is both the grand old man and the grim young one of public-interest medicine, one of the few doctors in his field.

"I come from a traditional medical background, so I don't mind learning how to do this stuff," Wolfe says, in his breathless, shy way of speaking, as if his words had to be dragged back from running down his throat.

He started with Nader in 1971, collaborating on a letter to the Food and Drug Administration warning of contamination in bottles of intravenous fluid -- and bringing about a recall of millions of bottles.

He has since won an exasperated opposition of medicos and bureaucrats.

Says William Cray, at the Pharmaceutical Manufacturers' Association: "His problem is an excess of zealotry. He tends to exploit every negative aspect of drug therapy to scare the consumer."

Scare he does. By 1977 he was going straight to HEW Secretary Joseph Califano asking for a ban on phenformin, an oral medication for diabetics. This year, he has aroused new fears about the cancer-causing properties of DES, a drug once used to help prevent miscarriages; and he has recently attacked a popular prescription painkiller called Darvon, which he says is both useless and lethal.

"The AMA loves to keep pointing out that I've never had a 'practice,' by which they mean fee-for-service medicine," Wolfe says. "But I never wanted one. Originally, I set out to be a chemical engineer, at Cornell. But I had a job back home in Cleveland one summer working in a plant that made hydrofluoric acid. Every day I'd go home with first-degree burns."

He transferred to Case Western Reserve, in Cleveland, and studied medicine under a socially oriented program designed and taught in part by Dr. Benjamin Spock. He then joined the Public Health Service ("I didn't want to go to Vietnam"), rejecting his membership in the AMA "It took about three months to get out -- they said I had to have permission from the Surgeon General") and working with the Medical Committee for Human Rights in causes including antiwar demonstrations.

In 1968, working as a researcher at the National Institutes of Health, Wolfe contacted Nader. Three years later he joined him to start crusading on subjects including breast surgery, pesticides, health insurance, privacy of medical records, hot dogs, toothpaste, cough syrup, contact lenses, hexachlorophene, saccharin, Alka-Seltzer, pacemakers, smoke detectors, dentistry, psychiatry, cigarette smoking and food additives.

The stoplight is red but Wolfe steps off the curb on P Street to check out the traffic anyway, being Mr. High-Energy Metabolism, a 41-year-old who forgot to shed the squirms and shrugs of adolescence.

"I am not a health food nut," he says, a little louder than necessary. The question hadn't been asked, but: "We shop at a supermarket. We eat well and survive."

We includes his daughter Hannah, 15, eldest of four daughters by his first wife, and Suzanne, a psychotherapist he married this year. They live in a townhouse he bought for $35,000 five years ago in Adams Morgan, which Wolfe is striding toward now. (Wolfe makes $25,000 a year.)

"People ask me if anything is safe. Well, I try not to tank up too much on animal fat. I try to reduce the amount of stuff -- additives -- going into me. But I'm not going to lose control of my life to some diet."

Recently, in fact, Wolfe angered part of his constituency by publicly doubting the wisdon of the large vitamin dosages which are the current fashion.

"A lot of public interest people take vitamins, apparently," he says, walking along Columbia Road huddled in his parka. "I tell them that they're chemicals, that they're made by the big drug companies just like the stuff they're fighting against, but they don't listen."

The glottal giggle rings out again, as he savors another iconoclasm. "I talked with that doctor who treated Mao Tse-tung all those years. I asked him about cigarette smoking in China. He said they'd like to ban it, but they have two provinces where the big business is growing tobacco. Same thing as here, right?" (The Chinese launched their first antismoking campaign earlier this year.)

Inside Wolfe's townhouse, it is bare wooden floors and plants and the air full of Wanda Landowska playing a Mozart sonata; walls bear prints in cluding "The Luncheon of the Boating Party," and Duchamp's bicycle wheel. The bookshelves are heavy with Nietzsche, Marx, Chekhov, Thoreau, Kierkegaard and other volumes such as "How to Stay Alive in the Woods" and "The Complete Book of Bicycling."

"I work long hours, but I never bring work home. Never," he says.

But what about the legendary Ralph Nader phone calls at strange hours?

"Ralph, well, let's just say that Ralph is a very sensitive individual and he picks up on feedback. Especially from wives."

So there's time for passions. Wolfe runs, for instance, but defies the marathon/mysticism fad to concentrate on the "the 400-meter dash. I ran a 54.8 last year. I ran the 440 in 52 or 53 in high school. I know a guy who's running much better times than he ran in high school."

In high school, Wolfe was writing letters to Albert Einstein as a member of the Atomic Science Club, and he used to hang out at little jazz clubs: "I was 15 and I'd sit there for six hours, listening to Brubeck, Gerry Mulligan, Chico Hamilton, Art Pepper, back when progressive jazz was happening."

He leans against the wall next to the phonograph, bouncing, rolling, peering, and you can picture that hip, happy kid growing up in Cleveland. Nowadays, that buoyancy must drive his enemies nuts.

"Listen to that!" he says. The music is Rudolph Serkin and the Cleveland Symphony playing Mozart's Concerto No. 20. "Cream! Cream!" he exclaims as Serkin pours out an edgeless glitter of piano notes.

"You ever see Serkin play? He's a madman, gets all hunched over with his tongue hanging out," and for a second Wolfe hunches over with his tongue hanging out, his fingers stabbing notes into the air. If only the American Medical Association could see him now.