A 59-year-old patient with schizophrenia developed Sjögren's syndrome. She also presented with the lupus anticoagulant attributed to long-term medication with chlorpromazine. Serial plasmapheresis treatments were performed to decrease the anti-coagulant activity. As a result, the activated partial thromboplastin time was temporarily improved, but the lupus anti-coagulant activity did not change. Because of her unstable emotional state, she continued to require chlorpromazine, but took a low dose of aspirin (87 mg/day) and never manifested any signs of thrombotic events. In view of the potential anti-thrombotic effects of chlorpromazine, it may not be necessary to use plasmapheresis in an attempt to reduce anti-coagulant activity among patients with chlorpromazine-induced lupus anti-coagulant.