It has been suggested that phospholipids and antibodies directed against phospholipids are important in the pathology of malaria. We have investigated the influence of immunizations with phospholipids on the course of subsequent blood-stage Plasmodium chabaudi chabaudi infections in ICR inbred mice. We observed a significant reduction in the parasitaemia following immunization with phosphatidylcholine (PC), but not with phosphatidylethanolamine (PE) immunization. At the peak of the infection, PC-immunized mice displayed a T-helper 2 (Th2)-type cytokine production pattern, whereas PE-immunized or non-treated controls displayed a cytokine production pattern of the T-helper 1 (Th1) type. Serum immunoglobulin transfer from PC-immunized mice protected naive mice in a similar fashion to PC-immunization, demonstrating that the observed reduction of parasitaemia was caused by the presence of PC-specific antibodies.