Individual belief and knowledge about cancer were shown to influence coping and compliance of patients. Supposing that the Internet information both has impact on patients and reflects patients' information needs, breast cancer web sites in English and German language were evaluated to assess the information quality and were compared with each other to identify intercultural differences. Search engines returned 10 616 hits related to breast cancer. Of these, 4590 relevant hits were analysed. In all, 1888 web pages belonged to 132 English-language web sites and 2702 to 65 German-language web sites. Results showed that palliative therapy (4.5 vs 16.7%; P ¼ 0.004), alternative medicine (18.2 vs 46.2%; Po0.001), and disease-related information (prognosis, cancer aftercare, selfhelp groups, and epidemiology) were significantly more often found on German-language web sites. Therapy-related information (including the side effects of therapy and new studies) was significantly more often given by English-language web sites: for example, details about surgery, chemotherapy, radiotherapy, hormone therapy, immune therapy, and stem cell transplantation. In conclusion, our results have implications for patient education by physicians and may help to improve patient support by tailoring information, considering the weak points in information provision by web sites and intercultural differences in patient needs. In December 2000, 42% of the European females were using the Internet with a clear upward trend (Kögel and Longo, 2001). Notably, women older than 50 years turned out to be the most active group of Internet users (Pichler and Gilg, 2001). In April 2001, Harris Interactive published results indicating that 75% of all adults who had access to the Internet used the Internet to collect health and medical information (Taylor and Leitman, 2001). In the USA, 54% of the Internet users searched the Web for health-related information compared to 26% in Europe, as demonstrated by a survey of Health On the Net (HON) Foundation in 2001. More females (51%) than males (49%) used the Internet to search for health-related information (HON, 2002). The main obstacle for patients is 'that there is so much information on the Net, big parts of it are incomplete, misleading, or inaccurate' (Achenbach, 1996). Correspondingly, Silberg et al (1997) had criticised the information on the Internet as not peer reviewed and pointed out the dangers of relying on such invalidated information.Due to the high incidence of mamma carcinoma (Weir et al, 2003), breast cancer web sites attract a high number of information seekers. In addition, breast cancer patients have gained a higher awareness of their disease during the last decades. They demand breaking taboos considering breast cancer, they refuse to hide their illnesses any longer, and many develop a different attitude towards their disease, which is known as 'fighting spirit' (Greer, 2000). Breast cancer patients, therefore, can be considered pioneers of a new type of self-confident patients (Biel, 19...