We report a case of brainstem infarction following a C5–C6 cervical transforaminal injection, a rare and serious neurological complication of this procedure. Cervical transforaminal steroid injection is a common therapy for patients with persistent cervical radiculopathy not relieved by conservative treatment, and is effective in 65–70% of cases. Unfortunately, this procedure may lead to serious complications such as neurological damage. These complications are rare but potentially fatal, as reported in our case. Complications could be due to three mechanisms: the technique itself, the cervical vascular anatomy and the properties of the product (corticoids). The neurological complications can be diagnosed through brain MRI. This case report focuses on the importance of a risk/benefit evaluation when performing this medical procedure.