Polymorphonuclear leukocytes (PMNL) are important components of the immunological defence system which protects the human organism from invading bacteria. Using a fluorescence microscopic method, we examined the influence of propofol and its solvent intralipid on phagocytosis and killing of Staphylococcus aureus and Escherichia coli by PMNL in vitro. Propofol inhibited (P < or = 0.001) phagocytosis of Staphylococcus aureus as well as Escherichia coli. Killing of Staphylococcus aureus (P < or = 0.001) and of Escherichia coli (P < or = 0.01) was suppressed. Intralipid, by itself, impaired phagocytosis of Escherichia coli (P < or = 0.05). Apart from that, intralipid produced no relevant effects. Additional clinical studies regarding the influence of propofol on PMNL function are recommended.