Sham Injections, Sham Pills And Sham Surgeries

Researchers have observed placebos producing changes in blood pressure and heart rate, as well as relieving pain, depression, anxiety and irritable bowel syndrome. Sham injections seem to work better than sham pills, large pills work better than small ones, and two pills are better than one. 

In one study, a surgeon gave patients a sham knee surgery, where the surgeon made an incision, but did nothing to the knee before sewing it back up. The patients were just as likely to find relief as those who underwent the procedure.