When I was a kid, we used to visit a property that was full of sassafras trees. We used to harvest and make our own root beer. I still have memories of that aromatic fragrance that permeated the house.I miss real root beer. Used to be Hires was real, Frosty was real. Now they are all artificial like Fanta. If I recall it was something about the original root flavoring that could be carcinogenic. Used to get a cold Frosty on the store bus.
Fast forward a few decades and you can't buy real root beer any more, and you can't even buy the ingredients to make real root beer. By law you're only allowed to buy root beer that's made with artificial flavorings. There are two reasons that real root bear doesn't exist any more, and that today's root bear doesn't use natural flavorings. You can choose which reason you'd rather believe:
Real root bear flavoring is derived from the sassafras fruit. Back in the 1960s it's primary ingredient, safrole, was banned because it it was thought to be carcinogenic, though the proof if it's carcinogenicity is still under debate.
Another reason that you can't buy real root beer that has safrole in it is because safrole has been banned internationally, according to the terms of the UN Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances. Why? Because the root beer essence safrole is one of many chemicals that can be used as a precursor in the synthesis of 3,4-Methylenedioxymethamphetamine, commonly known as Ecstasy. Current government regulations worldwide not only ban the drugs, but also highly regulate the chemicals that can be used to make them.
As a result of it's ability to be used as a precursor to the organic synthesis of MDMA the US DEA keeps natural root beer flavoring on the list of controlled List 1 Chemicals. Anyone who acts as a supplier of any chemical on the list is subject to rigid regulation and control measures. As a consumer, you can't buy it. Just like you can't more than an ounce of Lugol's Iodine solution any more because it can be used in the synthesis of methamphetamine.
So while one group of people believes that the FDA had banned safrole in the interest of public health, there's another group of medicinal chemists and toxicologists that know that the entire world has regulated safrole, in the name of public health, or as others will call it, The War on Drugs.