The sphenopalatine ganglion is close enough to the nasal lining to be reached with anesthetic through the nostril. That anatomical accident makes it one of the least invasive nerve blocks in medicine.
![Lateral fluoroscopic view during a sphenopalatine ganglion block, labeled to show the SphenoCath [soft nasal catheter] in position, the spheno-ethmoid recess and the Vidian or petrosal canal](https://headache.express/wp-content/uploads/2026/08/spg-fluoro-landmarks-v2.jpg)
What the ganglion does
It is a small collection of nerve cell bodies behind the nose, roughly level with the middle of the cheekbone, and it is the relay for much of the autonomic supply to the face. The tearing, the blocked nostril, the flushing and the drooping eyelid of a cluster attack are that system firing.
It also carries sensory fibers relevant to migraine and to facial pain, which is why the block has uses beyond cluster.
How it is done
You lie back or recline. A thin soft catheter is passed along the floor of the nostril and local anesthetic is delivered against the mucosa over the ganglion. It is held in place for a few minutes, then the other side is done.
Most people describe pressure and a bitter taste at the back of the throat rather than pain. The whole thing takes about fifteen minutes. No injection into the face, no imaging, no recovery period beyond sitting up slowly.
Honest expectations
The evidence for SPG blocks is real but more modest than for oxygen in cluster headache. Trials have generally shown a meaningful reduction in pain scores over the days following treatment rather than a reliable instant abort, and the effect size varies considerably between studies and between people.
It is a reasonable option when a headache is not responding to first-line treatment, when you cannot tolerate the usual drugs, or when you want to avoid an injection. It is not a guaranteed switch, and we would rather say that than oversell it.
Who it suits particularly well
- People in a cluster bout who need something in addition to oxygen
- Migraine with a strong autonomic component — the attacks that feel most “sinus-like”
- People who cannot take the usual acute drugs, including some who are pregnant
- Head and neck cancer pain in the midface, nose or palate, where the mouth may be too painful or too restricted for other approaches
- Upper-jaw distributions of persistent pain after dental treatment
That fourth case is worth dwelling on. When opening the mouth is limited by radiation fibrosis or surgery, a treatment delivered through the nostril is not merely convenient — it may be the only comfortable route.
After-effects and cautions
Minor and short-lived: a numb throat for an hour or so, a bitter taste, occasionally a brief nosebleed. You should not eat or drink until the throat numbness has resolved.
It is avoided if you have an active nasal infection or a recent nasal fracture.
Common questions
Does it involve a needle at all?
No. The anesthetic is delivered topically through a soft catheter in the nostril. See sphenopalatine ganglion block.
How soon would I know if it worked?
Some people notice a change within the appointment; more often the benefit shows over the following days. It is judged over days rather than minutes, unlike oxygen in cluster — see oxygen therapy.
Can I eat afterwards?
Not until the throat numbness has gone, usually about an hour. Swallowing with a numb throat is an aspiration risk. See SPG block.
Is it safe if I get frequent nosebleeds?
Tell us. Occasional minor bleeding is a known after-effect, and a bleeding tendency or recent nasal injury changes the calculation. Contact us to discuss.
Being seen at Headache Express. We treat migraine, cluster and other severe headaches in St. Louis, usually the same day. Please contact us before coming in so the right treatment is ready when you arrive.