Purpose: This study aimed to investigate the use of non-conventional medicine (NCM) among long-term cancer survivors and its links with healthy behavior. Methods: This study used data from the VICAN survey, conducted in 2015-2016 on a representative sample of French cancer survivors 5 years after diagnosis. Results: Among the 4174 participants, 21.4% reported using NCM at the time of the survey, including 8.4% who reported uses not associated with cancer. The most frequently cited reasons for using NCM were to improve their physical well-being (83.0%), to strengthen their body (71.2%), to improve their emotional well-being (65.2%), and to relieve the side effects of treatment (50.7%). The NCM users who reported using NCM to cure cancer or prevent relapses (8.5% of the participants) also used NCM for other reasons. They had more often experienced cancer progression, feared a recurrence, and had a poorer quality of life because of sequelae, pain, and fatigue. They also consulted their general practitioners more frequently and had changed their lifestyle by adopting more healthy practices. Conclusion: The use of NCM is not an alternative but a complementary means of coping with impaired health. Further research is now required to determine whether the use of NCM reflects a lifestyle change or whether it assists survivors rather to make behavioral changes. Implications for cancer survivors: The use of NCM should alert physicians to survivors' impaired quality of life. It might be useful to provide patients with NCM guidelines in order to inform their decision and to prevent unrealistic expectations.