They are the miracle pills that shouldn't really work at all. Placebos come in all shapes and sizes, but they contain no active ingredient. Now they are being shown to help They are the miracle pills that shouldn't really work at all. Placebos come in all shapes and sizes, but they contain no active ingredient. Now they are being shown to help treat pain, depression and even alleviate some of the symptoms of Parkinson's disease. Horizon explores why they work, and how we could all benefit from the hidden power of the placebo. 详情