Amy Donor Schachtel, modern day matchmaker for pharmaceutical companies, scours Hollywood from distant Essex Falls, N.J., in her quest for celebrities low on squeamishness yet high on empathy.

Her quarry: the perfect spokesperson for diseases ranging from the formerly unspeakable — urinary incontinence, irritable bowel syndrome — to lesser-known killers like melanoma.

Schachtel, a former publicist, first discovered how potent the marriage between celebrities and disease could be while working on a Schering-Plough campaign in the mid-1990s. Now, she spends months finding the right match from her East Coast base. She’s part of a growing phalanx of marketers searching for celebrities ready to call attention to maladies of the moment.

“The field is really booming and at the same time has become more selective about the right fit for the disease,” she says. “There has to be some sort of natural connection — a certain passion for it.”

Usually that means some sort of family tie to the disease. Former Wonder Woman Lynda Carter, for example, agreed to chat up I.B.S., as irritable bowel syndrome tends to be discretely abbreviated, because her mother is afflicted. In the course of a casting search for a cancer medication, Schachtel discovered Rob Lowe’s father had the disease and might be willing to talk about medicine available for chemo patients.

“It just doesn’t work if it’s not the right fit,” Schachtel says. “It’s not just a question of calling an agent like you would for a commercial, agreeing to a price and that’s it. There’s lots of research. Both sides want to make sure they’re comfortable with the message.”

“Most companies are looking for a celebrity who has the disease or has it in the family,” says Barry M. Greenberg, prexy of Hollywood-based Celebrity Connection. “This is not an assemblyline production. If anyone does a handful of these in a year, it’s extraordinary.”

The most effective spokesmen, he says, are celebrities with the disease themselves, such as Michael J. Fox with Parkinson’s disease or Christopher Reeves in his battle against spinal injury. Few would question their commitment or motives for raising awareness, just as few would question Katie Couric’s drive for colonoscopies following her husband’s demise from colon cancer or Tom Sherak’s tireless fundraising efforts on behalf of multiple sclerosis since his daughter was diagnosed with the disease.

The networking nature of showbiz also comes into play on the disease charity circuit. At last week’s L.A. benefit for an arterial lateral sclerosis group, headliner Brad Grey was able to enlist clients like Brad Pitt and Jennifer Aniston. Paul Simon performed. The presence of big names enhances visibility and raises funds — ALS, it is worth noting, was long known as Lou Gehrig’s Disease.

It gets murkier, however, when celebrities sign on to be a paid spokesman for a disease-related foundation or medication without necessarily disclosing their funding.

Bob Dole’s connection to Viagra is clear — he has appeared in their ads and talked frankly about his impotence. Kathleen Turner, Lauren Bacall and Kelsey Grammer’s wife Camille, on the other hand, have each talked up medications in interviews without disclosing what funds they might have been receiving from pharmaceutical companies for these endorsements.

Marketers and celeb handlers are quick to defend the appearance fees to high-profile clients, citing the “time is money” defense, but others aren’t quite as sanguine.

“Obviously, if they’re getting paid, it’s not altruism,” said USC prof Leo Braudy, author of “The Frenzy of Renown: Fame and Its History.”

“I don’t really count that as charity,” seconded Stacy Palmer, editor of the Chronicle of Philanthropy.

It used to be that medications for embarrassing afflictions — diarrhea, anyone? — were advertised in humorous commercials instead of earnest celebrity testimonials disguised as do-goodery. Not too surprisingly, there’s a lot of sensitivity about disclosure issues in the celeb camps.

Braudy believes celebrities should be more upfront about disclosing their financial incentive to discuss a disease. But Schachtel maintains she always discloses the connection in press materials in medical campaigns, but that the media interviewing her clients doesn’t always relay that information during interviews.

Greenberg, however, rails against the blurring between drug companies and non-profit medical causes, a development accelerated by freer TV ad spending. “Drug companies are creating self-serving philanthropic-sounding entities to use PR to promote their product,” contends Greenberg, who formed Celebrity Connections in 1985. “If you have hemorrhoids, there’s a drug to promote.”

Former Georgetown U. surgeon Jonathan Sackier makes no apologies for enlisting celebrities to increase medical awareness. “Doctors are lousy communicators on the whole and the truth of the matter is, people love celebrities,” says Sackier, the founder and chairman of Spotlight Health.

Spotlight has worked with Dole, Carnie Wilson and Larry King on awareness campaigns — each that affected them personally — and is supported by several pharmaceutical companies. “We use real stories with real people who happen to be celebrities,” Sackier says.

Like other celebrity wranglers, he swears by the impact these familiar faces have on awareness of diseases. He says some celebrities are involved on a purely altruistic level, while other need to be paid for their time. “I don’t see a problem with paying people for their time if they need it,” he says.

Greenberg says compensation can range from $30,000 to $300,000 for a day’s work all the way up to $1 million and stock options. “Price change when a celebrity is not in demand,” he says. “By and large, people have a value they attach to that time. Our job is to find out what that value is.”