A young woman, 25 years old, being treated for her veinous system with EucatexR (a drug including catechins) presented an acute intravascular hemolysis with an acute renal failure. The finding of anti-Eucatex and anti-catechins antibodies in the serum and on the red cells of the patient proved the immuno-allergic nature of this hemolysis. A renal biopsy showed lesions of acute tubular nephritis but no immune depots. The patient recovered after a treatment by hemodialysis.