Effects of ginger and expectations on symptoms of nausea in a balanced placebo design.

Objective: Ginger effects on (experimental) nausea have been described, but also strong placebo effects and sex differences when nausea is involved. The "balanced placebo design" has been proposed to allow better separation of drug and placebo effects.

Methods: Sixty-four healthy participants (32 women) were randomly assigned to receive an antiemetic ginger preparation or placebo, and half of each group was told to have received drug or placebo.