The herbal tea is ever popular, but local health experts advise caution.

Anyone who's had the misfortune of experiencing cancer, or is close to someone who has, likely has heard about every possible alternative therapy, herb, and supplement out there that might help conquer the disease. Take Essiac. Many survivors swear by the herbal tea, claiming it killed their tumours, sometimes even without the aid of chemotherapy or radiation. But while anecdotal evidence abounds, two local health professionals say to sip the stuff with skepticism.

Rene Caisse, a Canadian nurse, came up with the concoction in the 1920s. (Its title is her last name spelled backward.) Her formula, which she learned about from an Ojibwa healer, consists of four ingredients: burdock root, slippery elm inner bark, sheep sorrel, and Indian rhubarb root. Combined, the herbs supposedly cleanse the blood, boost the immune system, and help repair cells.

Caisse went on to operate her own cancer clinic in Northern Ontario from 1934 to 1942 and continued to give Essiac to people until the late 1970s. Before she died in 1978 at age 90, she gave the recipe for Essiac to the Resperin Corporation of Ontario. Other, similar products have since emerged, like Flora's Flor-Essence, which contains the four Essiac herbs plus watercress, blessed thistle, red clover, and kelp.

According to Barrie R. Cassileth's 1998 Alternative Medicine Handbook (W.W. Norton), proponents claim that Essiac can reduce the size of tumours and prolong the lives of many people with incurable cancer.

"Caisse believed that Essiac worked by attacking the tumor directly, first hardening it, then causing it to soften and break up, and finally discharging it from the body," the guide states.

Dr. Jim Chan, a naturopathic doctor based in Richmond, says he has used Essiac with many of his cancer patients but stresses that it's not a cure-all.

"I wouldn't say I would rely on it alone," Chan says. "I do use a lot of Essiac, but I combine it with a lot of other things, and people use it along with chemo. It would be detrimental to have any false expectations that left someone missing out on other effective, reasonable treatment.

"There have been encouraging anecdotal reports," he adds. "But I've ended up with a lot of people who were told that this was enough to treat them, so they stayed away from chemo or surgery. You shouldn't put all your eggs in one basket."

Lynda Balneaves, an assistant professor and Canadian Cancer Society research scientist at the UBC school of nursing, says that although some studies have been done on Essiac's anticancer properties in a laboratory setting and in mice, results have been contradictory, and large-scale human trials are lacking. According to the National Cancer Institute, a division of the Bethesda, Maryland–based U.S. National Institutes of Health, no results of clinical trials of either Essiac or Flor-Essence in people have been reported in peer-reviewed scientific journals.

One of the problems in testing the product, Balneaves says, is that the quality, potency, and effectiveness change from batch to batch, since no two plants are alike. She too emphasizes that Essiac shouldn't be seen as a first line of defence against cancer.

"Essiac has not been shown to be a cancer cure," Balneaves says. "It can't be seen as a replacement for primary treatment.

"People also need to inform their practitioner if they're taking this substance," she adds. "There haven't been a lot of side effects”¦but it could potentially have an interaction with other drugs."

For people considering Essiac, Balneaves recommends researching evidence-based resources, like the NCI (www.cancer.gov), New York's Memorial Sloan-Kettering Cancer Center (www.mskcc.org), and the B.C. Cancer Agency, which has a guide to unconventional therapies (www.bccancer.bc.ca).

According to the NCI, side effects of Essiac are nausea and vomiting, while those associated with Flor-Essence include increased bowel movements, frequent urination, swollen glands, skin blemishes, and headaches.

Essiac costs $38 for a 300-millilitre bottle through Finlandia Natural Pharmacy's on-line store (www.finlandiapharmacy.com), while a 500-milliltre bottle of Flor-Essence goes for $25. People are typically advised to drink the tea one to three times a day.