Dr. Elias Petrou, a Greek doctor and physiotherapist, came from America in 1935 where he studied and with a series of books he wrote and corresponding lectures he managed to change Greek society in a few years. His own actions with treatments of people suffering from serious or non-serious illnesses, in 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 intestinal function, from where most diseases originate according to natural hygiene and natural therapeutic science.
- Fruit therapy for natural toning of the body, treating many diseases but also as a smooth re-entry into diet after fasting.
- Alkaline diet for correction and increase of pH in the blood, as a preventive measure so that we do not get sick.
- Physical exercise for proper muscle function and elimination of toxins through burning in the body.
- Air therapy through exposure to clean environment and respiratory exercises.
- Sun therapy through exposure to the sun -obliquely in the shade and not directly- in moderation but consistently throughout the year, in order to acquire 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).