A simple method is presented for measuring people's illness cognitions--their common-sense representations of common illnesses. Data were collected from 1,628 different respondents who described a recent illness form 1 to 3 separate times over a 17-month period. A free-clustering task performed by a set of naive participants confirmed that these cognitions fall into the five components that have been previously noted: identity, time line, consequences, cause, and cure. These five components are found to be reasonably stable over time and across different illness episodes. Several consequences of these illness cognitions, in terms of changes in health-locus-of-control beliefs and different propensities to visit a doctor, are also noted. Specifically, controllable attributions for getting sick and personal responsibility attributions for getting better are associated with increased beliefs in Self-Control Over Health and decreased beliefs in Chance Health Outcomes; people with strong Identity and Cure components in their common-sense representations of common illnesses have a greater propensity to visit a doctor when feeling ill.