Unless you’re participating in a spelling bee or playing Fallout New Vegas, you probably don’t think about sassafras much, but you might still ingest it regularly. It is, or at least once was, the main flavourful ingredient in root beer.
Sassafras (a tree) and sarsaparilla (a vine) were traditionally used--along with other substances like licorice root, mint, nutmeg, and more--to flavour root beer. Recipes for root beer similar to what we know today date back to 1860, and sassafras root beverages date back even further, made by indigenous peoples for medicinal and culinary purposes.
But modern root beer doesn’t contain any real sassafras root anymore, why not?
Well, sassafras and sarsaparilla both contain safrole, a compound recently banned by the FDA due to its carcinogenic effects. Safrole was found to contribute to liver cancer in rats when given in high doses, and thus it and sassafras or sarsaparilla-containing products were banned.
But more recent studies have actually failed to find evidence that the effects seen in rats occur in humans. This, and the fact that several other (still legal) foods, like the aforementioned nutmeg, also contain safrole, makes the ban seem less science based and more the result of fear.
So, modern root beer is flavoured most often with artificial sassafras, though sometimes with safrole-free sassafras too. More important than checking the safrole content of your beverage, though, might be checking the alcohol content. Traditional root beer was usually alcoholic, whereas modern root beer is rarely fortified with ethanol and is a favourite of kids everywhere.