Reflexology is a system of massage that works on the principle that there are microsystems on the hands and feet that correspond to various body parts. Stimulation of these microsystems by massaging or squeezing them can have a beneficial effect on glands, organs, and other parts of the body. A therapist uses only his hands and no other instrument when manipulating the microsystems present in the hands and feet. Reflexologists attribute the success of the therapy to their being able to control and manipulate life force energy or Qi; an idea borrowed from traditional Chinese medicine.