According to the International Center for Reiki Training
A Brief Overview:
Reiki is a Japanese technique for stress reduction and relaxation that also promotes healing. Reiki is administered by "laying on hands" and is based on the idea that an unseen "life force energy" flows through us and is what causes us to be alive. If one's "life force energy" is low, then we are more likely to get sick or feel stress, and if it is high, we are more capable of being happy and healthy.
The word Reiki is made of two Japanese words - Rei which means "God's Wisdom or the Higher Power" and Ki which is "life force energy". Reiki actually translates to "spiritually guided life force energy."
A Reiki treatment feels like a wonderful glowing radiance that flows through and around you. Reiki treats the whole person including the physical body, emotions, mind and spirit creating many beneficial effects that include relaxation and feelings of peace, security and well being.
Reiki is a simple, natural and safe method of spiritual healing and self-improvement that everyone can use. Reiki has been effective in helping virtually every known illness and malady and always creates a beneficial effect. Reiki also works in conjunction with all other medical or therapeutic techniques to relieve side effects and promote recovery.
While Reiki is spiritual in nature, it is not a religion. Reiki has no dogma, and there is nothing you must believe in order to learn and use Reiki. In fact, Reiki is not dependent on belief at all and will work whether you believe in it or not.
Because Reiki comes from God, many people find that using Reiki puts them more in touch with the experience of their religion rather than having only an intellectual concept of it.