The toxic oil syndrome (TOS) is a chemically induced autoimmune-like reaction in humans. The etiologic agent(s) have so far not clearly been identified. A short overview is given on this disease which is associated with a unique antibody specificity to cryptic epitopes of C-reactive protein in affected patients. In addition a murine model for TOS is described which suggests that genetic susceptibility might play a role in inducing a similar syndrome in mice. These differences are reflected in the immunological alterations and cytokine production caused by the toxicant.