The placebo effect is a perfect example of the minds power over physical disease. And illness of the body registers as being an illness in your consciousness. When your consciousness shifts to one of health, the body must also shift to align to health.
Next time you feel sickness coming on, try visualizing healing on yourself and stay in a healthy positive state of mind. Meditate daily, and do something fun and uplifting. Don't let the thought of being sick take over your being. You will be amazed at how much healthier you feel when you align yourself with the presence of health and wholeness.