Researchers randomly assigned 31 patients with wounds to the forehead to receive either Botox or a placebo injection right after the wounds were closed.

Seventy-seven patients received intravenous progesterone, and 23 were given a placebo injection.

Singer and Schachter asked themselves a single question, "do the injections of epinephrine produce symptoms of sympathetic nervous system (SNS) discharge as compared to the placebo injections?"

For comparison, others got placebo injections of saline solution (salt water) with no medicine.

This scientific study was based on thirty people with bruxism who received Botox injections into the muscles of mastication and a control group of people with bruxism who received placebo injections.

Children who weren't infected with hepatitis A were separated into two groups, one receiving the experimental vaccine and the other receiving a placebo injection.

He said that the three large-scale clinical trials of visco-supplementation for knee osteoarthritis "show no effect compared with placebo injections of saline."

Fifteen patients received placebo injections.

Fifteen will receive placebo injections and 30 will receive three injections of the investigational vaccine over 2 months and will be followed for 1 year.

Two-thirds of the participants were given a series of seven vaccinations over three years, while the other third were given the same number of placebo injections.