Many of the profound effects of staphylococcal septicaemia are thought to be the result of entry of enterotoxins into the systemic circulation. The aim of this study was to investigate the disposition of staphylococcal enterotoxin A (SEA) in the rat and its possible removal from blood. SEA labelled with 125I was administered intravenously (250 micrograms/kg) to rats. The blood clearance of SEA showed a biphasic pattern; an initial fast disappearance (half-life c. 3 min) was followed by a slower one (half-life c. 2 h). Thirty minutes after injection of 125I-labelled SEA, most of the radioactivity was concentrated in the kidneys, indicating that renal excretion was the main route of elimination of SEA. The adsorption capacities of polymer-coated activated charcoal (DHP-1 and Adsorba 150C), uncharged resin (Amberlite XAD-7), anion exchange resin (Dowex-1) and polymyxin B matrix were assessed by measurement of the equilibrium adsorption isotherms for SEA. DHP-1 charcoal, Amberlite XAD-7 resin and Dowex-1 resin adsorbed similar amounts of SEA in human plasma. Plasma perfusion experiments were performed in vitro with small columns containing either charcoal or resin adsorbents. Over 4 h perfusion, DHP-1 charcoal removed 50% of the initial amount of 125I-SEA, Adsorba 150C charcoal 8.1% of SEA and Amberlite XAD-7 resin 32.5% of SEA. These results suggest that it may be feasible to develop the adsorbent columns for direct removal of SEA from the plasma of patients with staphylococcal septicaemia.