The simplest form of meditation is to follow your breath. Meditation helps to raise the consciousness in order to balance mind-body-emotions. 
Meditation with visualisation enables the body onto a better pathway to healing and brings about a state of well-being.

Disease, means dis-ease, ie "not at ease".  When there is unease, there is imbalance, and the result is illness. Imbalance in the flow of energy, the making and using of all chemicals in the body such as hormones, enzymes and neurotransmitters, changes in acidity, moods, indigestion, sleep patterns and many more.

So how can meditation and visualisation help? The very root cause of disease is negative energy, that can be negative thoughts, emotions, poor lifestyle and stresses of all kinds. Thoughts carry energy. Negative thoughts create negative circumstances; positive, healthy, loving thoughts create more positivity in one's life.

Negative energies enter our physical through the etheric body or our aura. That means, somewhere there is an opening, a hole, a kind of tear in the aura or etheric body that is allowing the negative thoughts in. They are likely to "bounce off" if the auric and etheric shield is whole. This where meditation and visualisation techniques are helpful, they help to "re-build" the patient.

Meditation and visualisation can benefit:

Stress conditions

Chronic illness

Aging

Weight

Infertility

Spiritual issues

Relationship issues

Addictions, phobias, traumas and abuse

Improve self-esteem

Bereavement

Other very personal and psychological issues that have not been solved with other methods have often resolved with meditation. It only takes about 15min meditation daily to transmute negative energy and instigate deep healing.