Truth Serum
Truth Serum is any chemical that reduces ones ability to resist a suggestion. Generally they are sedatives, like alcohol. Even dentists have noticed that Nitrous Oxide can be used to hypnotize. The state of hypnosis is reduced pain, reduced resistance, and less ability to say no. Alcohol is well noted for its ability to remove resistance to questions. The amount that is used has to be specific. Generally anything that reduces ones alert level.