For many families of pediatric cancer patients the use of complementary/alternative medicine (CAM) is an accepted adjunct to conventional therapy, even if data regarding effects and risks are scarce. This report provides information about the prevalence of CAM use and reasons for CAM use among pediatric cancer patients. We report the studies available in the literature concerning pediatric oncology and summarise what is known about beneficial effects and risks that could be attributed to certain complementary and alternative methods. Frequently used CAM like mind-body medicine, nutrition (incl. diets and vitamins), homeopathy, anthroposophic medicine, phytotherapy, and acupuncture are highlighted, as were CAM with a lesser percentage of users, bearing special risks (e.g. interactions with chemotherapy) and/or are costly for their users. Physicians should be aware that a substantial percentage of their patients may use CAM without telling them. Physicians need to be open-minded and should discuss CAM with parents, because parents often think that CAM is natural and, therefore, safe. On the other hand, physicians often lack basic knowledge concerning CAM leading to an avoidance of talking about CAM with parents. A professional differentiation between potentially useful and potentially dangerous CAM is necessary to aim at minimising the risks for CAM users.