A patient is presented who developed pulmonary artery embolism and thrombocytopenia with various arterial clots several days after an ankle joint osteosynthesis, which finally caused the amputation of the right arm. Unfractionated heparin was applied for the prevention of postoperative thrombosis. Obviously as a consequence of the liberation of toxic metabolites from the gangrenous lower arm, the patient developed septic shock which was exacerbated by a severe pneumonia caused by methicillin-resistant S. aureus bacteria (MRSA). Laboratory investigations showed an antibody (IgG) induced thrombopenia mediated by all low molecular weight and unfractionated heparins. By eliminating heparin and further treatment with a low molecular weight heparinoid (ORG 10,172), platelet count rose sufficiently and thrombotic process ceased completely. Septic shock was successfully treated by fluid replacement, antibiotics and inotropic substances.