Sassafras oil is an essential oil sourced from the sassafras tree. Safrole, its active ingredient, is used in the production of the drug MDMA, more widely known as a street drug called "ecstasy."
Although sassafras oil was once widely used as a fragrance and flavoring agent, safrole is now recognized as a carcinogen, meaning that is a cancer-causing agent.
Since 1960 the United States and Canada have banned sassafras oil (other than trace amounts of safrole) from foods and medications. Sassafras oil should not be consumed orally or used externally as even small amounts can be fatal.
 
Purported Health Benefits 
Sassafras and safrole have been used to detoxify and/or treat a variety of medical conditions, including:
Inflammation
Mucositis (inflammation of the mucous membranes of the mouth and throat)
Rheumatoid arthritis
Sprains
Syphilis
Urinary tract disorders
There is no scientific evidence to support the use of sassafras or safrole for these health benefits. In addition, medical experts caution that using sassafras or safrole oil can have serious health consequences.
Sassafras Oil for Head Lice 
Another popular purported benefit of sassafras oil is in the treatment of head lice. However, there's a lack of scientific support to support this claim, as well. Do not use it for head lice, as it can have serious health consequences even when used externally.
If you're seeking a natural remedy for head lice, there's some evidence that shampoo containing neem (an herb used in Ayurvedic medicine) may be helpful. In addition, a number of essential oils including tea tree, peppermint, lavender, and eucalyptus oils have been found to destroy head lice in laboratory experiments. However, more research is needed before any of these remedies can be recommended for the treatment of head lice.
Sassafras Tea Risks and Purported Benefits 
Sassafras tea is a beverage made from the roots of the sassafras tree. The tea is sometimes touted as a natural remedy for a broad range of health conditions including bronchitis, the common cold, the flu, arthritis, eczema, psoriasis, and high blood pressure. Also said to "purify the blood," sassafras tea contains a considerable amount of safrole.
Due to safrole's potentially toxic effects, consumption of sassafras tea is not recommended. Adverse effects associated with the consumption of sassafras tea include itchiness, confusion, inflammation of the skin, vomiting, and difficulty breathing. While it's possible to purchase sassafras tea products from which the safrole has been removed during production, it might be wise to avoid sassafras entirely due to the potential toxicity.
Instead, many other teas may offer health-enhancing benefits and aid in the treatment of certain health issues. For instance, studies show that green tea may help lower your cholesterol, preserve brain health, and strengthen bones to fight off osteoporosis.
A type of herbal tea, hibiscus tea shows promise as a natural means of controlling blood pressure and cholesterol. Black tea, meanwhile, may help fight diabetes and protect against heart disease. And rooibos (a tea made from the South African plant Aspalathus linearis) may have some beneficial effects on the immune system.
Possible Side Effects 
Sassafras root bark and oil contain compounds (including safrole) that are carcinogenic. Even safrole-free sassafras has been linked to tumors. In addition to acting as a carcinogen, sassafras oil may have a number of toxic effects when consumed.
Symptoms of sassafras oil toxicity include abdominal pain, diarrhea, dizziness, hallucinations, low blood pressure, nausea, rapid breathing, rapid heartbeat, shallow breathing, and vomiting.
Use of sassafras oil is also associated with liver damage. In addition, there's concern that consumption of sassafras oil during pregnancy can result in miscarriage.
Like other essential oils, sassafras oil applied topically is absorbed through the skin. 
If you're considering using sassafras (or any form of alternative medicine), it's crucial that you talk with your doctor first. Self-treating and avoiding or delaying conventional care may have serious consequences.
Environmental Concerns 
Production of sassafras oil is contributing to the destruction of rare trees in southwest Cambodia, according to the nonprofit conservation group Fauna & Flora International (FFI). In 2009, FFI partnered with the Cambodian Ministry of Environment to identify, raid, and shut down two illegal sassafras oil factories in the Cardamom Mountains of Cambodia. The FFI states that sassafras oil production not only harms the trees themselves but causes significant damage to the entire forest ecosystem.