"I shall please" is the Latin translation of what medical treatment?

A placebo ("I shall please" from placeo, "I please") is a substance or treatment with no active therapeutic effect. A placebo may be given to a person in order to deceive the recipient into thinking that it is an active treatment. In drug testing and medical research, a placebo can be made to resemble an active medication or therapy so that it functions as a control; this is to prevent the recipient(s) and/or others from knowing (with their consent) whether a treatment is active or inactive, as expectations about efficacy can influence results.

Research suggests that for psychological reasons, some placebos are more effective than others. Large pills seem to work better than small pills, colored pills work better than white pills, an injection is more powerful than a pill, and surgery gives a stronger placebo effect than injections do.

The placebo effect has been controversial throughout history. Notable medical organizations have endorsed it, but in 1903 Richard Cabot concluded that it should be avoided because it is deceptive. Newman points out the "placebo paradox" – it may be unethical to use a placebo, but also unethical "not to use something that heals". He suggests to solve this dilemma by appropriating the meaning response in medicine, that is make use of the placebo effect, as long as the "one administering... is honest, open, and believes in its potential healing power".