Acute diarrhoea is worldwide the second most frequent disease after acute inflammations of the airways. Chronic diarrhoea is a less frequent disease, nevertheless the GP, specialist in internal medicine or gastroenterologist encounters it very frequently. For correct understanding of basic diagnostic and therapeutic principles of diarrhoea knowledge of its etiopathogenesis is necessary. In the submitted review the author mentions the functions of the small and large intestine and their part in the development of diarrhoea. He gives also the definition and classification of diarrhoea. The author presents the basic characteristics of osmotic, secretory, inflammatory, motor diarrhoea and diarrhoea associated with increased intestinal filtration. The basic diagnostic and therapeutic principles are in the last part of the review which has an educational character.

        Key words: igestive tract iarrhoea Pathogenesis Classification Clinical aspects Treat ment