<b>Introduction:</b> Oncological second opinions are becoming increasingly important given more complex treatment strategies, simultaneously more patients use complementary and alternative medicine (CAM), and many comprehensive cancer centers initiate integrative medicine programs. The present study focuses on analyzing the effects of a second opinion in relation to attitudes toward CAM. <b>Methods:</b> In this prospective study patients (n = 97) with a diagnosis of breast cancer or gynecological malignancies who had requested a second opinion received a questionnaire before and after the second opinion concerning their attitudes toward CAM. <b>Results:</b> The majority of patients had breast cancer (72.2%, n = 70). Only 6.2% (n = 6) stated that they had been informed about CAM by the doctors who treated them first, 21.6% (n = 21) had received information about it when seeking the second opinion. After the first opinion, 42.3% (n = 41) wanted to try CAM, the same proportion trusted orthodox medicine alone. After the second opinion, 24 patients (24.7%) wanted to try CAM, while 38.1% (n = 37) relied exclusively on orthodox medicine. There was a significant correlation between an increased patients’ need for information and interest in CAM (p = 0.02). <b>Conclusions:</b> Today, aspects of CAM still are very often no part of oncological first and second opinions. This might hence lead to discouraging patients to try out CAM and therefore integrative medicine programs in comprehensive cancer centers might be problem-solving.