Sensible people can be driven to foolishness by relentless, unforgiving, chronic pain.

And quacks know it.

So does Joyce, a 60-year-old Northern Virginia woman who wasted $2,000 on a three-day trip to Mexico in quest of a miracle. Joyce, who asked not to be identified by her real name, suffers from a particularly severe type of rheumatoid arthritis that cripples her some days and always hurts.

The disease flared up in her thumbs 10 years ago, spread across her hands and eventually affected most of the joints in her body. Since then she has tried nearly every proven and experimental anti-arthritis treatment conventional medicine has to offer -- including surgery and an arsenal of such powerful drugs as cortisone, Cytoxan, methotrexate, penicillamine and cyclosporin.

Nothing worked.

"Your hands look and feel as if you've hit each one across the knuckles with a hammer," she says. "You're watching your hands begin to self-destruct."

She would reach out to pick up a paper plate and realize she couldn't do it. She would enter a room and stand there, unwilling to sit down for fear of the pain of getting out of the chair. She could no longer hold a teacup with just one hand.

Well-meaning friends sent her huge copper bracelets and prescribed a daily tablespoon of vinegar and honey. Worse, when she chose not to try such unproven remedies, friends and relatives sometimes accused her of not really trying to get well.

One day she picked up a free magazine in a health food store and saw an article on a clinic in Mexico promising miraculous relief from arthritis.

"All my joints were going to pieces again," she recalls. "You think: What have I got to lose? Cortisone is going to crumble my bones anyway."

Encouraged by her family but without telling her doctor, she obtained the clinic's telephone number and made a reservation.

She and her son flew to Texas, and drove a rented car across the border to the Mexican clinic. She checked into a nearby Motel 6, registered at the clinic and joined about 30 other patients sitting on benches in the waiting room.

When her turn came, she received a blood test and the first of three daily injections of a secret-formula drug. After three days she left with renewed hope, a printout of test results and a plastic bag full of bottles of red and white pills.

Joyce propped the pills on the car dashboard, as the people at the clinic had advised, and when she and her son reached the border, the guards waved them right through.

The trip, including travel, lodging and clinic fees, cost about $2,000.

Joyce took the pills for several weeks, before realizing they weren't working any better than anything else. Humiliated and fearful, she finally summoned the courage to tell her doctor what she had done.

As soon as the doctor saw her puffy moon-face, he knew what kind of drug she had been given at the clinic in Mexico.

"It was cortisone and aminopyrene," says Dr. Henry Roth, Joyce's rheumatologist. Both drugs have serious potential side effects.

"They go to the clinic and get the injections, and they feel terrific," Roth says. "Then they come home and the family doctor is left to pick up the pieces when the effects wear off."

Joyce is among the tiny minority of arthritis patients who have "raging, aggressive disease" that doesn't respond at all to prompt and intensive care, Roth says. He praised her for her courage and her willingness to work with the Arthritis Foundation to educate people about her crippling disease.

In hindsight, Joyce knows the trip to Mexico was a waste of time, money and hope. But she still remembers why she felt she had to go.

"It's that terrible cycle of pain. You're constantly searching for some relief. How easy it is to indulge in something terribly foolish that you wouldn't try if you were able to sit back and analyze it cold-bloodedly.

"But we can't."