The disease referred to eponymically as Whipple's disease (WD) in medical literature was thoroughly described by the American physician and pathologist George Hoyot Whipple (1878-1976) in 1907 and given a temporary denomination of "intestinal lipodystrophy". According to literature, WD is rare, but its precise incidence has not yet been established. Familial incidence of the disease is acknowledged, and its immunogenetic pathogenesis is assumed. The incidence ofWD is prevailingly observed in middle-aged men (mean age 55), exceptionally at child age - the ratio being 3 to 6 for men and women, respectively. 1. Clinical diagnosis is based on symptoms in the GIT region and, in rare cases, on extraintestinal symptoms. Clinical symptomatology includes: abdominal pain with persistent diarrhoea (steatorrhoea), symptoms typical of malabsorption connected with weight loss, fevers, polyarthritic symptoms, swollen lymph nodes and, in part of patients, skin hyperpigmentation. Anaemia and hypoalbuminaemia (reduced IgA) are typically detected in laboratory tests. Rarer extraintestinal symptoms of the disease are of a diverse nature: cardiac lesions, cerebral lesions, ocular symptoms, conspicuous or even tumour-like enlargement of lymph nodes, lesions of the hemopoietic system. The clinical course ofWD is of progressive or remittent nature and the disease is fatal without treatment. Long-term therapy with antibiotics, especially a combination oftetracyclines (doxycyclin) and corticoids (dexametazone), or chloramphenicol in case of cerebral lesion, have a significantly positive effect on the course and prognosis of WD. From the point of view of pathology, WD is a multisystem infectious disease (Tropheryma whipplei) primarily affecting the GIT (39, 47, 52, 103) or different extraintestinal locations. Due to the known diversity of clinical symptoms, no clinical-diagnostic standard has been established for WD. Differential diagnosis includes different multisystem diseases, primarily malignant lymphomas (especially Hodgkin's disease). From the pathogenetic point of view, we can either assume the effect of a particular cytokine (or TNFalpha) activating macrophage phagocytosis or, if its production is normal, a disorder or defect of the respective receptor in the macrophage cellular membrane. The identification of "Whipple's bacteria" - Tropheryma whipplei - gen. nov. et sp. nov. was made possible by modern molecular biology research methodologies. Its cultivation allows both for the acquisition of the specific antibody and of detailed knowledge of its genoma (PCR, 16S rRNA sequencing).