Summary1. Twenty cases of Henoch-Schoenlein Purpura (HSP) are described in adult patients from 24 to 76 year old.2. The clinical characters are analyzed. The frequency distribution of the symptoms is the same as for the children : purpura (100 %), arthralgia (90 %), intestinal bleeding (57 %) and hematuria (57 %). The degree of the renal involvement determines the prognosis.3. The allergic etiology of the HSP was demonstrated with certainty in 3 of our patients. The causal antigens were respectively sulfa drugs, cow milk and extracts from B. coli.4. The recent advances made in the physiopathology of the disease are discussed.5. No particular therapy can be presently advocated with certainty.