Here are a pair of pieces from Policy Options, on the ethics of doing research on something we already know doesn’t work. Should we subject human beings to risk — or even inconvenience — to “test” something that is patently ridiculous?
The 2 pieces represent a bit of a tempest in a teapot. Both authors agree that homeopathy is useless. They simply disagree somewhat over whether it could ever be ethically OK to engage in further testing, and whether it would in some way be harmful to explicitly forbid such testing.