Dr. Elias Petrou, a Greek physician and physiotherapist, came from America in 1935 where he studied and, through a series of books he wrote and corresponding lectures, managed to change Greek society within a few years. His actions, through treatments of people suffering from serious or non-serious illnesses within a few days and mainly in a natural way, made Greeks believe in him and talk about the new "revolution" of natural hygiene. The therapeutic methods he applied were based on the following:
- Fasting for detoxification and correction of bowel function, from which most diseases originate according to natural hygiene and natural therapeutic science.
- Fruit therapy to naturally stimulate the body, treating many ailments and also as a smooth reintroduction to diet after fasting.
- Alkaline diet to correct and raise the pH in the blood, as a means of prevention so that we do not get sick.
- Physical exercise for the proper functioning of the muscles and the elimination of toxins from the body through burning.
- Aerotherapy through exposure to a clean environment and breathing exercises.
- Heliotherapy through exposure to the sun - indirectly in the shade and not directly on the skin - in moderation but steadily throughout the year, to achieve the bronze color that is indicative of a healthy person as he said, (not the sickly color of the solarium, nor the excesses of the sun).