The complete pathogenesis of toxic shock syndrome (TSS) has yet to be elucidated. Unmasking the complex interactions among bacterial products, host factors, and possibly tampon components requires a suitable in vivo model. For this purpose, subcutaneous chambers implanted in rabbits were inoculated with Staphylococcus aureus isolated from patients with TSS. Infected rabbits developed illness characterised by multisystem involvement that included periportal inflammation of the liver, erythrophagocytosis in the spleen and lymph nodes as well as extreme vascular dilatation and epithelial lesions similar to those described in patients with TSS. Concentrations of serum creatinine (P less than 0.03) and triglycerides (P less than 0.04) were significantly raised in rabbits infected with TSS strains compared with rabbits infected with non-TSS strains of S. aureus. Both TSS and non-TSS strains of S. aureus produced fever and diarrhoea, but TSS strains were significantly (P less than 0.05) more lethal and more likely to produce respiratory distress and lowered blood pressure. This model may help to prove or disprove proposed mechanisms for the development of TSS.