This is one of those weird stuff in life. A&W Root Beer causes headaches for some people. Every other soft drink (eg. Coca Cola, Pepsi, etc) doesn't. If you're one of those people who kena headaches when you drink Root Beer, and only Root Beer, at first you might think it's just a coincidence. Afterall, based on the ingredients on the label, there's nothing in Root Beer that isn't also in Coke or Pepsi. But when you kena this Root Beer headache over and over again, you google this online and realize, "Hey I'm not the only one! A lot of other pple kena also! KNN PCB A&W Root Beer!"
https://www.google.com.sg/#q=root+beer+headache
https://www.google.com.sg/#q=root+beer+headache
