Illustration: Istvan Banyai

It may scare you to realize this—but you, and not your doctors, are in charge of your medical care. They're not gods, and you're not a wuss. Got that? O shows how to fight (nicely) for the best possible treatment.

Having watched her mother die of breast cancer, Sharon Doumas, 51, felt oddly serene when her own diagnosis was handed down. "The minute the doctor told me I had breast cancer, a calm feeling came over me and I knew I needed a double mastectomy," says the teacher's aide from New Hampshire. But what happened next stunned her. Her surgeon flat out refused, insisting that she have a lumpectomy with radiation. Doumas recalls her doctor saying, "Oh, no, you don't want a mastectomy; you're just panicking." She remembers looking the surgeon in the eye and saying in a steady voice, "Do I look like I am panicking to you?"

Doumas found a new surgeon and got the double mastectomy she wanted. Though lumpectomy was a viable option, Doumas didn't want to live with the uncertainty that the cancer might return. But how many of us have the chutzpah to debate our doctors, especially in the face of a serious diagnosis? We need to find a way: The time to stop blindly following doctors' orders is now. Kate Clay, program director of the Center for Shared Decision Making at Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, says today's unprecedented number of new drugs and high-tech procedures means patients need to take control. "Don't assume the system is going to work for you. Make it work for you."

The first hurdle for many people is shifting their notion of doctors as benevolent dictators. Your physician is your employee, says Steven Katz, MD, an internist and professor of medicine and health management and policy at the University of Michigan in Ann Arbor. Expect the same amount of customer service from the doctor's office or hospital as you'd expect from any other business. "Patients should be more demanding of their doctors," says Katz, especially when it comes to their own medical files. "People want banks that offer online access, yet when it comes to medical records—or the ability to e-mail your doctor—people say, 'Gee, I don't want to be a bother.'"

Even if you're healthy and haven't had much experience jousting with your doctor's office, you should assert yourself in small but meaningful ways. For instance, call before your appointment and ask if the doctor is running on time. If she is running late, the appointment is for routine care (say, a Pap smear), and you don't want to wait, reschedule, says Clay. "The only time you should wait to see a physician is in the emergency room."

If, like Doumas, a serious diagnosis thrusts you onto a merry-go-round of appointments, tests, and procedures, there are easy ways to remain in control.