Another medical phenomenon that provides us with a tantalizing glimpse of the control the mind has over the body is the placebo effect. A placebo is any medical treatment that has no specific action on the body but is given either to humor a patient, or as a control in a double-blind experiment, that is, a study in which one group is given a fake treatment. In such experiments neither the researchers nor the individuals being tested know which group they are in so that the effects of the real treatment can be assessed more accurately. Sugar pills are often used as placebos in drug studies. So is saline solution (distilled water with salt in it). Even surgery has been used as a placebo.

In the last half century the placebo effect has been extensively researched in hundreds of different studies around the world. We now know that on average 35 % of all people who receive a given placebo will experience a significant effect, although this number can vary greatly from situation to situation. Conditions that have proved responsive to placebo treatment include migraine headaches, angina, allergies, fever, the common cold, acne, asthma, warts, various kinds of pain, nausea and seasickness, peptic ulcers, psychiatric syndromes such as depression and anxiety, rheumatoid and degenerative arthritis, diabetes, radiation sickness, Parkinsonism, MS, and cancer.

An asthma patient was having an unusually difficult time keeping his bronchial tubes open. The doctor ordered a sample of a potent new medicine from a pharmaceutical company and gave it to him. Within minutes the man showed spectacular improvement and breathed more easily. The pharmaceutical company wrote the Dr. and told them that they had sent him a placebo by mistake instead of the potent new medicine. His expectations were the healing modality.

There's a lot written on Placebos, if you want more research check the Internet or other books.