In this video, I mentioned the Japanese study in which poison ivy was rubbed on the forearms of boys known to be allergic to the plant. In the first part of the experiment, a poison ivy leaf was rubbed on the forearms of teenage boys known to be allergic to it, yet, the boys were told the leaf being rubbed on their arms was from a harmless plant; they go no allergic reaction. Later, a harmless leaf was rubbed on their arms, but the boys were told it was poison ivy; they got severe allergic reactions.
This is just one of many studies reported on in my book In Your Own Hands: New Hope for People with Chronic Medical Conditions—Mindfulness-Based Practices for mastery and Wellbeing. In hundreds of randomized controlled trials and case studies, patients were able to learn how to use their minds to effect positive changes in physiological functioning.