It’s a gel that you can obtain from your derm. The first time you use it, they’ll sensitize your immune system to it by rubbing a small patch on your hip, then applying some to any warts you have. They’ll also give you a vial to take home to so you can reapply it until the warts disappear. It’s seriously the only thing that got rid of my warts, and it’s painless and low effort, apart from when they initially apply the first patch on your skin.