A 4‐year‐old Quarter Horse mare was seen in the field by Colorado State University's Equine Sports Medicine Service for a 5‐week history of marked sensitivity to touch near the withers/shoulder region. On examination, the mare showed a marked adverse response to light touch over the caudal neck and withers region. Diagnostic imaging of the caudal neck, withers and shoulder region showed no significant abnormalities. Vital parameters, complete blood count and chemistry profile were also within normal limits, as was a reproductive ultrasound examination. The mare received dexamethasone, gabapentin, magnesium/vitamin E, prednisolone and aquapuncture with no improvement in clinical signs. The mare was then started on pure crystalline cannabidiol (250 mg by mouth twice daily), which resolved the clinical signs after 2 days.