Scopolamine was the first drug to be called a “truth serum,” and was used in police interrogations in the 1920s and 1930s. But it’s not the only alleged truth serum: pentothal, sodium amytal, and even plain old alcohol have all been rumored to make people confess true facts and feelings. TV journalist Michael Mosley even tested pentothal on himself to see if it would compel him to tell the truth. On a smaller dose, he was able to lie about his occupation. On a larger dose, he readily divulged what he did for a living, later explaining that it didn’t even occur to him to lie.