Explicit cross-cultural learning experiences in medical education are provided within the context of implicit experiences provided by a greater "hidden curriculum." The authors conducted a content analysis of 983 cases presented in the 1996-1998 year one and year two curriculum at the University of Minnesota Medical School to determine in what ways they might embody elements of the hidden curriculum, i.e., how they either supported or undermined explicit messages about diverse patient populations. Cases were coded for demographic variables, potential risk factors, and diagnoses or presenting problems. The findings revealed that cases featuring males out-numbered those featuring females; this ratio differed across courses, and appeared to differ from the actual epidemiology of the conditions. Sexual orientation was specified infrequently. When sexual orientation and behavior were specified, these appeared in the context of a risk assessment for particular diseases (e.g., HIV infection). Most cases did not provide racial or ethnic descriptions. For many of the ethnic descriptors, links to genetic, cultural, or socioeconomic factors were apparent; no such link was apparent when the racial terms "white" or "Caucasian" were used. Analysis of the 983 cases shows that the pattern of demographics and associations of particular groups with diseases or risk factors in cases conveys messages, as does the lack of mention of sexual orientation and race or ethnicity. These messages are inconsistent with and may undermine the formal multicultural medical curriculum. The results suggest a need for formal deliberation of this aspect of the curriculum by curriculum planners.