Does Judaism allow placebos where the person thinks it does something, and is thereby cured, even though the item does nothing?
Is this gnevas da'as (or some other issur), or because it can help them it's permitted to mislead them this way.
Nishmat Avraham writes on this (vol 2, p.12)
[Placebo trials] are permissible provided that
- the patient gives his full consent after being fully informed of the possible risks and that he may be put into one of other group randomly
- all patients, regardless of which group they will belong to, will continue to receive the medication they were getting until now. The experimental drug or placebo is merely added to their present treatment
PS. As a reminder the author, Dr. Abraham S. Abraham, is a leading physician in Israel. He doesn't address "the law of the land" in his response