Background: Increasingly, patients with cancer are asking for additional, complementary therapy options for treating the side effects of oncological therapy. Thus, the members of the Breast and Bowel Center Nahe at the Sankt Marienwörth Hospital Bad Kreuznach decided to define the content of this type of counseling for patients before treatment. Methods: In 2018, a team of internal oncologists, gynecological oncologists, radio-oncologists, nutritionists, psycho-oncologists, and study nurses met several times to define the content of counseling. To inform the team, an intensive literature review was conducted. Results: Counseling content was determined for complementary treatment options for the most frequent side effects of oncological therapies. Counseling sessions were formulated as frontal lectures (slide presentations), given at regular intervals for patients and relatives. These lectures were highly appreciated by patients. Conclusion: These counseling sessions increased patient understanding of both useful complementary measures and harmful measures they should not use.