For seriously ill patients, almost any therapy can start to sound good. Several years ago, one hot alternative therapy for cancer was shark cartilage, and a few animal studies suggested that it might actually help. Researchers in the Midwest ran a clinical trial of shark cartilage.

What the researchers wanted to know: Does shark cartilage help patients with advanced cancer?

What they did: People with incurable breast cancer or colon cancer were eligible to join the study. Once joining, they were randomly assigned to take Benefin Shark Cartilage powder or a placebo that looked—and smelled—the same. (The researchers said the powder was so strong that people passing near the storage area could smell it.) Patients stayed in the study for as long as they could tolerate the powder, which was taken three or four times a day in water or juice. Once a month, the patients were asked about symptoms such as nausea and any cardiovascular events. Eighty-three cancer patients joined the study and started taking powdered shark or the placebo. Neither they nor anyone treating them knew which treatment they were taking.

What they found: Taking shark cartilage did not extend patients' lives or improve their quality of life. Also, researchers say, people found the treatment difficult to follow. Many patients dropped out within a week, and only about half stuck with their assigned treatment for a month. After six months, only 10 percent were still taking the treatment. The longest anyone stuck with it was 14 months, for one patient on the placebo.

What the study means to you: Shark cartilage didn't show a benefit for people with incurable cancer. Given that people couldn't even stay in the study, the researchers express a "lack of enthusiasm regarding further study" of powdered shark cartilage.

Caveats: The study was originally supposed to enroll 660 patients, but recruitment was so slow, and patients were so unenthusiastic about adhering to the treatment, that the study was stopped early. Since the study was smaller than expected, the researchers may have missed a small positive—or negative—effect of shark cartilage. On the other hand, a therapy isn't much use if patients won't stick with it.

Find out more: Read an article from the National Cancer Institute that reviews studies on cow and shark cartilage.

The National Center for Complementary and Alternative Medicine (part of the National Institutes of Health) has questions and information to consider if you're thinking about using alternative medicine.

Read the article: Loprinzi, C.L., et al. "Evaluation of Shark Cartilage in Patients With Advanced Cancer." Cancer. July 1, 2005, Vol. 104.