Clinicians are increasingly asking questions about family history to inform decision making, but the quality of decisions rests on the quality of information provided by the patient. In families with genetically transmitted diseases, research has found a strong collective understanding of inheritance and risk, developed through constant communication between family members. Here, we explore whether there are similar processes in families with more common conditions like heart disease, asthma or osteo-arthritis. From in-depth interviews with lay people, we found that families created a culture of 'health talk', especially between sisters. Caring for other family members was demonstrated through sharing vital health information; on the other hand care could be shown by not worrying family members by talking about possibly inherited illness. Patterns of inheritance and health were talked about in participants' families (resemblance, similar conditions and affected body areas). From these, a picture developed of what the family was 'like' in health terms. Overall, experiential knowledge and family narrative was interwoven with expert discourse to form a complex understanding of medical family histories.