The participants in the study, conducted by the Independent Cancer Treatment Research Foundation in Arlington Heights, Ill., were given small amounts of shark cartilage powder mixed in fruit juice three times a day before meals. After six weeks of this therapy, doses were slightly increased because no measurable results were found.

Why Study Shark Cartilage?

Researchers said this study was conducted in large part because the public is turning to alternative and complementary therapies in greater numbers. The Food and Drug Administration (FDA) does not currently test herbs, vitamins, or therapies unless they will be used as prescription drugs.

Shark cartilage and bovine cartilage contain compounds that keep blood vessels from forming-- which may prevent tumors from getting nourishment. Many cancer patients became interested in using shark cartilage therapy after the publication of the book, Sharks Don't Get Cancer, by William Lane, PhD.

"Scientists have believed for over 35 years that since sharks do not appear to develop as much cancer as humans, there may be something in their systems that protects them from getting cancer," said Gabriel Feldman, MD, director of prostate and colorectal cancer for the American Cancer Society. Therefore, scientists began studying shark cartilage to determine whether or not it is helpful in treating cancer, he said.

Why Doesn't This Work?

"Everybody in [the field of oncology] knew way before this article was published that shark cartilage cannot possibly be beneficial," said Barrie Cassileth, PhD, author of The Alternative Medicine Handbook.

Scientists say the reason shark cartilage does not help patients is because the molecules of the active ingredient in shark cartilage are too large to be absorbed into the bloodstream when taken by mouth. Therefore, the shark cartilage passes in and out of the body without a chance to break down and be used at all.

On the other hand, Dr. Cassileth pointed out, "There are possibly chemical components in shark cartilage which may have a tumor-reducing effect." These chemicals, however, cannot be obtained by taking available over-the-counter shark cartilage supplements.

The National Cancer Institute (NCI) is currently conducting phase III clinical trials on a new cancer drug made from a liquid shark cartilage extract to determine if it is effective. NCI and a Montreal-based biotechnology corporation, Aeterna Laboratories, Inc., are testing Neovastat on 550 patients with advanced small-cell lung cancer at hospitals throughout the US and Canada. All patients in the trial will get standard treatment for small-cell lung cancer, which is chemotherapy, and sometimes, radiation. Half of the participants will receive the drug following standard treatment while the other half will receive a placebo.

NCI NIH

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