There are certain products that are indispensable to civilized man and whose very use is a proof of civilization. Soap is one of these products. We recall here the famous words of liebig, who maintained that a people is all the more civilized and comfortable, the more soap it uses. This fact is materially well established by the dry figures of statistics. In ancient times, even up to the Middle Ages, soap was completely unknown or very little used. People were content with perfuming their clothes and bodies with odorous substances. The question of which people invented soap making is one that cannot be answered with precision. It seems that in the Middle Ages, in some countries, an alkaline solution was used to wash clothes, and to clean fine sheets, certain plant roots were marinated in water, which formed a foamy liquid (saponaria, saponaria). Despite the progress made by industrial chemistry, we still find some areas where the preparation of soap is the same as our ancestors did a thousand years ago: tallow, lime and wood ashes.