A series of in vitro studies were designed to determine whether di-(2-ethyl-hexyl)-phthalate (DEHP)-plasticized polyvinyl chloride (PVC) and DEHP itself initiated an inflammatory response in both human and rat blood. Additionally, the effect of methanol washing of the PVC on the inflammatory response was studied in both blood types. Blood from both species was exposed to first, no material; second, ground DEHP-plasticized PVC; third, methanol-washed ground DEHP-plasticized PVC; and fourth, known concentrations of DEHP. The expression of the integrin CD11b was employed as a marker of the inflammatory response. After 20 minutes' exposure to PVC, CD11b expression increased to 210 +/- 32% of baseline in human blood and to 238 +/- 21.7% in rodent blood. Both blood types showed an increase in CD11b expression with increasing concentrations of DEHP (214 +/- 40.8% of baseline levels in human blood and 237 +/- 14.5% in rodent blood at the highest concentration). Methanol washing resulted in a significant moderation in CD11b upregulation in both blood types; 117 +/- 27% of baseline in human and 150 +/- 14.7% in rodent. These results support the hypothesis that DEHP-plasticized PVC and DEHP itself are proinflammatory in blood from both species, and suggest that the rodent is an appropriate model for studies of this nature.