Is a spinal tap dangerous?

A spinal tap, or lumbar puncture, is a simple procedure that is generally recognized as safe, according to Mayo Clinic. However, as with any medical procedure, a spinal tap comes with a few inherent risks.

During a spinal tap, a doctor inserts a small needle in between two vertebrae in the patient's lower back, according to Mayo Clinic. A small sample of cerebrospinal fluid is drawn out with the needle to be tested for illnesses and infections. This procedure is relatively safe, but it can cause headaches, back discomfort after the procedure, slight bleeding at the puncture site and brain stem herniation in severe cases.