A person's belief is seen as a set of assumptions, depending on perceptions, and formed with the influence of experiences and social culture. With the aim of understanding the beliefs about the genesis of their illness, 118 (59 + 59) women with different stages of breast cancer were interviewed. Half of the sample had chosen complementary care in an anthroposophical hospital, and the other half was a matched group. Qualitative content analysis was used. Three themes emerged: (1) belief in a link to life lived (71%), (2) heredity as the sole genesis (4%), and (3) rejection of the question (25%). Under beliefs in a link to life lived, external aspects to the patient's own life (eg, diet and lifestyle) were cited, as well as inner aspects such as psychosocial problems and stress. The findings show that women are well informed about medical facts, although their beliefs reveal a holistic approach. The women's beliefs, where inner psychosocial factors are uppermost, point to a reverse of the causal ranking of medical advisors. The difference between the groups was that the matching sample was more likely to reject the influence of possible causes from life lived. In a caring perspective, women's perceptions of the genesis of their illness are in some cases turned to creative health activities that may increase well-being.