Cervicogenic headache is a disabling headache where pharmacological management have limited effect Thus  non-pharmacological management is warranted Our objective was therefore to investigate the efficacy of chiropractic spinal manipulative therapy versus placebo (sham manipulation) and control (continued usual but non-manual management) for cervicogenic headache in a prospective 3-armed single-blinded  placebo  randomized controlled trial of 17 months’ duration