This is from the British Columbia Cancer Agency webpage. As I read it, the risk is from the safrole oils in the bark of the root. We don't use the bark for making strips. The wood itself should have less of these oils compared to the amounts concentrated in the bark. However, you may note that if you consume enough Safrole to make it 1% of your diet your testicles may atrophy. (Another good reason to not consume sawdust.)

Paul Jacobson - - - - - - - - -

SASSAFRAS TEA

Many individuals with cancer may wish to investigate unconventional or

unproven therapies. This information, cited from the medical literature and

other sources, is intended to help cancer patients and their families in their

objective evaluation of unconventional therapies.

Summary

There is evidence that sassafras tea is toxic and is not effective in treating

cancer.

Description / Source / Component

This tea is made from the young root of sassafras, Sassafras abdidum. The

active ingredient is safrole. (Stich)

Sassafras root bark contains sassafras oil that is at least 70 percent safrole.

(Herbert)

Safrole is also a component of many essential oils, such as star anise oil,

micranthum oil and camphor oil. (Homburger)

History

"Sassafras was always popular in folk medicine, being regarded by rural

people as a spring tonic or purifier of the blood." (Haines)

Sassafras is used for medicinal purposes as well as for a beverage. Aromatic

oil derived from the sassafras root bark was formerly much utilized in

flavoring confections, soft drinks, and pharmaceutical products. Such use

was banned by the U.S. Food and Drug Administration in 1960 after safrole

was found to be hepatocarcinogenic (liver cancer-causing) in the rat. (Stich)

Toxicity / Risks

"Safrole is a substance that is toxic to the liver and can cause cancer in

animals." (Herbert)

"Several naturally occurring aromatic ethers, of which safrole

[1-allyl-3,4-(methylenedioxy)-benzene] is one example, are

hepatocarcinogens." (Bolton)

Safrole is a chemical carcinogen which can induce DNA modification. (Tan)

"In concentrations of 1% of the diet, safrole is toxic, producing weight loss,

testicular atrophy, and bone marrow depletion. It also induces hepatomas

(liver cancer)." (Homburger)

A 72-year-old woman drank sassafras tea up to 10 cups a day and developed

diaphoresis and hot flashes. When the woman "stopped drinking the tea, the

diaphoresis and hot flashes promptly resolved." (Haines)

Results of a study of the effect of safrole on mouse liver "demonstrated a

sequential development of altered hepatocyte populations leading to

hepatocellular carcinomas (HPC) in safrole-treated mice. The

transplantability of the HPC indicated their malignant nature." (Lipsky)

"We have shown in preliminary pharmacological experiments that certain

aqueous and alcoholic extracts prepared from sassafras root bark are capable

of eliciting a variety of pharmacological responses in mice, including ataxia,

ptosis, hypersensitivity to touch, central nervous system depression and

hypothermia. Safrole is also a potent inhibitor of certain liver microsomal

hydroxylating systems, a property that could lead to toxicity problems if

drugs metabolized by these enzymes are administered together with

sassafras teas. . . . To ensure safe and effective drug therapy, it would seem

appropriate for physicians to evaluate their patients in terms of

extemporaneous herb tea usage and to discourage these practices whenever

feasible." (Segelman)

"In 1960, the Food and Drug Administration in the U.S. showed that safrole,

the major chemical constituent of the aromatic oil in sassafras root bar, was

hepatocarcinogenic (causes liver cancer) in rats." (Haines)

"Carcinogenicity of safrole following transplacental exposure of the mouse

fetus and exposure of the neonatal mouse via the mother‘s milk was

investigated in mice by intragastric administration of the agent to pregnant

and lactating females. . . . Renal epithelial tumors were observed in 7% of

female offspring exposed to safrole in utero; none of the other experimental

and control animals developed these tumors. Only male offspring nursed

during the preweaning period by mothers treated with safrole developed

hepatocellular tumors. In contrast, direct administration of safrole, beginning

at the time of weaning and continuing for the duration of the experiment, led

to a significantly high incidence of hepatocellular tumors in females, but not

in males. Eighty-six percent of the liver tumors observed in females were

hepatocellular carcinomas with a high rate of pulmonary metastasis. The data

suggest that safrole or its metabolites came into contact with fetuses by

crossing the placenta and with infants through its excretion in milk to exert

the perinatal carcinogenicity." (Velsselinovitch)

References

Bolton JL, Acay NM, Vukomanovic V. Evidence that

4-allyl-o-quinones spontaneously rearrange to their more electrophilic

quinone methides: potential bioactivation mechanism for the

hepatocarcinogen safrole. Chemical Research in Toxicology 1994

May-June;7(3):443-450.

Haines JD, Jr. Sassafras tea and diaphoresis. Postgraduate medicine

1991 Sept 15;90(4):75-76.

Herbert V, Barrett S. Vitamins and "health" foods: the great American

hustle. Philadelphia, PA: George F. Stickley Company, 1981:168.

Homburger F, Boger E. The carcinogenicity of essential oils, flavors,

and spices: a review. Cancer Res 1968;28:2372-2374.

Lipsky MM, et al. Biology of hepatocellular neoplasia in the mouse.

1. Histogenesis of safrole-induced hepatocellular carcinoma. JNCI

1981;67(2):365-371.

Segelman AB, et al. Sassafras and herb tea: potential health hazards.

JAMA 1976;236(5):477.

Stich HF. Carcinogens and mutagens in the environment V.III.

Naturally occurring compounds: epidemiology and distribution. Boca

Raton,Florida:CRC 1983;7-9.

Tan D, et al. Both physiological and pharmacological levels of

melatonin reduce DNA adduct formation induced by the carcinogen

safrole. Carcinogenesis 1994 Feb;15(2):215-218.

Vesselinovitch KVN, et al. Transplacental and lactational

carcinogenesis by safrole. Cancer Res 1979;39:4378-4380.

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