Acute intravascular haemolysis (AIH) sometimes occurs in patients with sepsis or bacteraemia, mainly due to clostridia or Salmonella sp., and may be a life-threatening condition. We describe a case of AIH in a 75-yr-old woman with chronic cholelithiasis. Blood and stool cultures were repeatedly negative, but the massive microspherocytosis, typically observed in clostridia infections, oriented our diagnosis. The patient was treated with antibiotics and for a rapid worsening of her conditions, which could have led to the onset of a multi-organ dysfunction syndrome (MODS), with plasma exchange and, subsequently, haemodialysis, with satisfactory results.