“Complementary and alternative medicine (CAM) therapies may be used as a non-pharmacological approach to chronic pain management. Twenty-six reviews (207 clinical trials, >12,000 participants) about 18 CAM modalities, falling under natural products, mind and body practices or other complementary health approaches were included. Inhaled cannabis, graded motor imagery, and Compound Kushen injection (a form of Chinese medicine) were found the most efficient and tolerable for chronic pain relief. When reported, adverse effects related to these CAM were minor.” https://www.ncbi.nlm.nih.gov/pubmed/28669581