Sassafras Tree: History, Traditional Uses, and Critical Safety Facts

1.9K

The sassafras tree (Sassafras albidum) is one of the most distinctive native trees of eastern North America, with a rich history of use spanning centuries. Its aromatic root bark and leaves have long captured the attention of herbalists, flavour chemists, and medical historians alike.

However, a critical piece of context is often missing from popular descriptions of this plant: the compound responsible for its characteristic scent and most of its traditional medicinal uses — safrole — is classified as a probable human carcinogen and has been prohibited as a food additive in the United States since 1960 by the U.S. Food and Drug Administration (FDA). [FDA, 21 CFR §189.180] This article covers the plant’s history, chemistry, folk uses, regulatory status, and — most importantly — what you need to know about safety.

What Is the Sassafras Tree?

Sassafras belongs to the laurel family (Lauraceae), the same botanical family as cinnamon and avocado. The North American species Sassafras albidum is native to the eastern United States, growing from Maine south to Florida and west to Iowa and Texas. It typically reaches 20–30 feet in height, though specimens over 60 feet have been recorded. The tree is best recognised by its unusual leaf variation: a single tree may carry oval, mitten-shaped, and three-lobed leaves simultaneously — a quirk that makes sassafras instantly identifiable once you know what to look for. [Britannica, 2023]

All parts of the plant are aromatic. Crushing a leaf or scraping a twig releases a warm, spicy scent that once flavoured root beer and was used across countless traditional preparations. However, this aroma comes primarily from safrole — a compound that has reshaped how the plant is regulated and used today.

Scientific name: Sassafras albidum (Nutt.) Nees  |  Family: Lauraceae  |  Parts used historically: root bark, trunk bark, leaves

A Long History of Traditional Use

Native American Uses

Long before European contact, many Indigenous peoples of eastern North America used sassafras for a range of purposes. Infusions made from the root bark were employed to bring down fevers, treat diarrhoea, and relieve rheumatic pain. The plant was also used topically in poultices for skin irritations and wounds.

European Discovery and Early Folk Medicine

Spanish explorers encountered sassafras in Florida around 1538 and noted that Native peoples used it as a fever remedy. The tree subsequently attracted enormous interest in Europe, where it was promoted — with considerable enthusiasm but limited evidence — as a cure for syphilis and a general purifying tonic.

In North American folk herbal tradition, sassafras became one of the most widely used spring tonics. Herbalists combined it with other plants such as sarsaparilla, echinacea, burdock, and licorice as a seasonal blood cleanser. It was also used in preparations for skin conditions, arthritis, and gout. Root beer, which originated as a medicinal drink, was for a long time made by simmering sassafras root bark with sugar and water.

These traditional uses reflect the plant’s cultural and historical significance. However, it is important to distinguish between historical tradition and current safety evidence — and the evidence now points clearly in one direction.

What Makes Sassafras Aromatic — and Why That Matters

The trunk and root bark of the sassafras tree contain an essential oil composed roughly 80% safrole, along with smaller amounts of pinene, phellandrene, and eugenol. [FDA, 21 CFR §189.180] Safrole (chemical name: 4-allyl-1,2-methylenedioxy-benzene) is the compound that gives sassafras its characteristic warm, spicy fragrance — and it is also the reason the plant’s bark and oil are now prohibited from food and drink products in the United States.

Safrole itself is not the direct problem. When the human body metabolises safrole, it converts it into a compound called 1′-hydroxysafrole, which is a more potent carcinogen than safrole itself. This is further converted into an unstable derivative that can bind directly to DNA, forming what scientists call DNA adducts — chemical damage to genetic material that can trigger the mutations associated with cancer development. This mechanism has been documented in rats, mice, and, critically, in human tissue samples.

Why Sassafras Root and Bark Are No Longer Considered Safe for Consumption

The FDA Regulatory History

Animal studies conducted in the late 1950s demonstrated that safrole reliably caused liver tumours in rats and mice. Acting on these findings, the FDA issued an order on December 3, 1960 (published in the Federal Register, 25 FR 12412) declaring that any food containing added safrole, oil of sassafras, or sassafras bark intended for imparting safrole to another food is adulterated under federal law. This ruling is codified at 21 CFR § 189.180. In 1977, the FDA extended the ban specifically to sassafras bark used in tea. [FDA, 21 CFR §189.180]

The National Toxicology Program (NTP) classifies safrole as “reasonably anticipated to be a human carcinogen” — a classification based on consistent evidence from multiple animal species and plausible mechanisms of action in human cells. [NTP Report on Carcinogens] Memorial Sloan Kettering Cancer Center (MSKCC), one of the world’s leading cancer hospitals, states directly: “Safrole and oil of sassafras has been banned as a food additive by the FDA due to carcinogenic concerns, and should not be used to treat medical conditions.“ [MSKCC, 2023]

Acute Toxicity

The safety concern is not limited to long-term cancer risk. Sassafras essential oil is acutely toxic when swallowed. Even small amounts can cause serious poisoning, with symptoms including abdominal cramps, vomiting, rapid or pounding heartbeat, low blood pressure, dizziness, and — at higher doses — seizures and loss of consciousness. Recovery from the resulting liver and kidney damage can take months. Children are especially vulnerable; a few drops of sassafras oil can be fatal for a young child.

A Note on Dose and Context

Some critics of the ban argue that the animal studies used doses far higher than a person would consume in a cup of tea, and that many common spices (nutmeg, black pepper, star anise) also contain trace amounts of safrole. These are reasonable points to acknowledge. The FDA’s position, however, reflects the precautionary principle: when a substance demonstrates carcinogenicity through a well-established biological mechanism and safer alternatives exist, there is no good public health rationale to maintain its use as a food or medicine. The concentration of safrole in sassafras root bark (~80% of the oil content) places it in a different category from the trace amounts found in culinary spices.

What Parts of the Sassafras Plant Are Considered Safe?

Not every part of the sassafras tree carries the same risk. The safety concern is specific to the root bark, the trunk bark, and any product derived from them. The following table summarises the current understanding:

Part of plant / product	Safety status	Reason
Sassafras root bark / tea	Strongly avoid	Contains ~80% safrole — banned by FDA; linked to liver cancer in animals
Sassafras oil (essential oil)	Strongly avoid	Acutely toxic even in small amounts; can cause seizures, organ damage
Safrole-free sassafras extract	Generally permitted	FDA allows when safrole is undetectable; used in commercial root beer flavoring
Sassafras leaves (dried / filé powder)	Generally considered safe	Safrole is negligible or absent in leaves; widely used in Creole cuisine
Sassafras wood / bark (topical)	Limited evidence	Occasional traditional topical use; avoid if skin is broken or irritated

Filé Powder: The Culinary Exception

If you have eaten gumbo in Louisiana, you have almost certainly consumed sassafras without realising it. Filé powder — made from dried, ground sassafras leaves — is a traditional Creole seasoning and thickener. It is legal, widely sold, and considered safe because sassafras leaves contain negligible or undetectable amounts of safrole. The FDA allows its use in cooking. Filé powder is not a medicinal concentrate and does not carry the risks associated with root bark or oil.

Potential Drug Interactions and Health Risks

Laboratory research indicates that safrole inhibits several cytochrome P450 enzymes in the human liver — specifically CYP1A2, CYP2A6, and CYP2E1. [MSKCC, 2023] These enzymes are responsible for metabolising a wide range of medications, including some antidepressants, blood thinners, and certain anaesthetics. Inhibiting them can cause medication levels to rise unexpectedly, potentially leading to adverse effects or toxicity. If you take any regular prescription medication, this is a reason to discuss any interest in sassafras-derived products with your prescriber.

Sassafras tea has also been documented to cause profuse sweating (diaphoresis) and hot flushes, which may be uncomfortable or problematic for people with certain cardiovascular conditions.

Who Should Avoid Sassafras Root Products?

Based on current evidence and regulatory guidance, the following groups should not use sassafras root bark, sassafras oil, or concentrated sassafras extract (unless it is certified safrole-free):

• Pregnant individuals: Safrole may cause miscarriage. There is no safe level during pregnancy.
• Breastfeeding individuals: Safrole can transfer to breast milk. Avoid entirely.
• Children: Even small amounts of sassafras oil can be fatal for young children.
• People taking sedatives or CNS depressants: Risk of excessive drowsiness due to combined effect.
• People with liver disease: Any additional liver burden from safrole is inadvisable.
• Anyone taking regular prescription medications: Due to CYP enzyme inhibition (see above).
• Anyone without medical supervision: Given the FDA ban and carcinogenicity classification, internal use of root bark or oil is not recommended under any circumstances without guidance from a knowledgeable healthcare professional.

HEALTH DISCLAIMER This article is for educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Sassafras root bark and sassafras oil are banned as food additives by the U.S. FDA and are not recommended for internal use. Always consult a qualified healthcare professional before using any herb, supplement, or natural remedy — especially if you are pregnant, breastfeeding, taking prescription medications, or managing a chronic health condition.

Frequently Asked Questions

Related Reading on Natural Health Message

• Sarsaparilla Plant: Benefits, Uses, and Evidence

• Rheumatoid Arthritis Diet: Best Foods for Joint Health

• 11 Foods That Cause Gout — and What to Eat Instead

• Herbs for Skin: Over 100 Plants for Skin Issues

• Licorice Plant Health Benefits

References

1. U.S. Food and Drug Administration. 21 CFR § 189.180 — Safrole. Code of Federal Regulations, Title 21. Originally published in the Federal Register, December 3, 1960.  → View source

2. Memorial Sloan Kettering Cancer Center (MSKCC). Sassafras — Herb Overview. Integrative Medicine Service.  → View source

3. National Toxicology Program (NTP), U.S. Department of Health and Human Services. Report on Carcinogens — Safrole.  → View source

4. Encyclopaedia Britannica. Sassafras (Sassafras albidum). Updated by Melissa Petruzzello.  → View source

5. Newberne P, Smith RL, Doull J, et al. The GRAS status of safrole in root beer. Food and Chemical Toxicology, 1999.  → View source

6. Electronic Code of Federal Regulations (eCFR). 21 CFR Part 189 — Substances Prohibited from Use in Human Food.  → View source