A person with a toothache usually touches his cheek where he feels the pain, while someone with a bellyache instinctively soothes it by putting a hand on his tummy.
Just about everyone would agree that laying a hand on a part of the body that's not well could have a calming effect.
This is a principle of Reiki, an esoteric treatment originating in Japan that has spread through Western Europe bringing controversy along with it.
"Reiki is a Japanese word for life energy," said Reiki instructor Wolfgang Niedermeyer of Bielefeld. When someone undergoes a Reiki treatment, energy from the practitioner is transferred to his patient. This is how, according to the theory, people depleted of energy can fill their tanks and get on the right course.
Many critics, however, consider the controversial treatment pseudo science.
"The practitioners say that patients can feel the flow of energy while they are being treated, but the effect has not been scientifically proven," said Lutz Hertel, chairman of the German wellness association in Dusseldorf.
Reiki can even be bad for one's health in part because of practitioners' assertions that in cases of acute coronary disease it can be used instead of conventional medicine.
This is the key problem with Reiki: Practitioners give the impression that they can heal their patients, said Hertel. According to German law, the only healing treatments allowed in Germany are those conducted by doctors and practitioners of holistic medicine.
Even the Lutheran Church in Germany has joined the discussion over Reiki, warning people to stay away from "unrealistic promises about cures, especially when urgently needed medical care is not carried out because of it".
Reiki practitioners vehemently resist such criticism, saying the method raises the quality of life and general satisfaction. Author Oliver Klatt of Berlin is convinced that it is authentic, saying it "releases stress, enlivens people and can promote the healing process".
Belivers cannot say exactly how Reiki works. "Certain hand positions are taught to people who learn Reiki, but the end effect is, it is all very intuitive," said Niedermeyer, who has practiced Reiki since 1990. "There is no fixed scheme." Thus, what exactly helps ease a headache, for example, can't be generally stated.
What is clear is that a patient lies down for the approximate 60-minute treatment and the practitioner lays his or her hands on part of the body for a few minutes then changes to another part of the body.
Despite his deep reservations, Hertel said Reiki has a good side.
"When you want to relax, Reiki is among the most widely spread practices," he said. Laying hands on someone could provide comfort or have a relieving effect. But he added, "One should not expect anything else from Reiki."