Benemei S, Appendino G, and Geppetti P (2010) “Pleasant natural scent with unpleasant effects: Cluster headache-like attacks triggered by Umbelularia californica”. Cephalalgia, Feb 1, 2010 (click author to see paper)
AUTHORS’ ABSTRACT: Umbellularia californica, a shrub or tree indigenous to southwestern Oregon and northern California, is commonly known as headache tree, probably because it is reported that its scent can cause headache. Here, we report the case of a 69-year-old Italian gardener, affected during his young adult age by cluster headache, who, 10 years from his last cluster episode, developed shorter-lasting cluster-like headache attacks after and at any time he was exposed to U. californica scent. The present case indicates that, even though endogenous mechanisms causing the cluster headache were no longer present, susceptibility to exogenous triggers remains active in this patient, and suggests that identification of the constituent(s) of U. californica responsible for triggering cluster headache-like attacks may help in the understanding of the hitherto elusive mechanism of cluster headache.
Dr. Sewell’s comment:
I had never head of the “headache tree” before reading this paper, although apparently it is ubiquitous in the San Francisco Bay area, which I have visited many times. In fact, I will be back there next month, and will seize the opportunity to bring some leaves back with me. Also known as the “California Bay Laurel”, the leaves can be used in cooking (and are available online from some spice stores) as a somewhat stronger substitute for bay leaves.
So here is the story of a 69 year-old Italian who started to have cluster headache at age 22, for two months every two years, persisting for 25 years. Eventually, he grew out of them, as 50% of cluster headache sufferers do, but ten years later he was pruning an Umbellularia Californica when the smell caused an immediate cold sensation in his left nostril—the same side he used to have cluster attacks—followed by a left-sided cluster attack, that fortunately died away after about ten minutes. He forgot all about it until a few months later, when he was pruning the same tree, and the same thing happened! Suspecting that the tree was somehow responsible, he took some of the leaves from the tree, crushed them, and sniffed them. The same thing happened again—a cold sensation, then a ten-minute cluster attack! After that, he avoided the tree.
Ten years after that, Dr. Benemei of the University of Firenze (Florence) in Italy heard the story and became very excited, as I would have also. He called the patient and asked the gardener if it would be okay to publish his story. He agreed, and then spontaneously went back to the tree and sniffed it again. Exactly the same thing happened.
So what was going on here? Nobody knows. The California bay laurel is nicknamed the “headache tree”, supposedly because prolonged exposure to its fragrant smell can cause a headache, but the Native Americans also apparently used the leaves as a treatment for headache. Certainly the link with cluster attacks hasn’t been noticed before.
Dr. Silvia Benemei speculates that the umbellulone, which is a strong pungent chemical found in the leaves and responsible for its smell, might be responsible for triggering the attacks. I think this might be jumping to conclusions; there are a lot of chemicals present in any plant, and even the non-smelly ones can have an effect. Either way, finding a chemical that can reliably trigger cluster attacks might provide clues as to how best to stop them, so it will be interesting to see what Dr. Benemei comes up with!
Thank you for providing this information. My cluster headaches had been in remission for 8 years until two weeks ago. While doing some research to investigate new treatments, I came across this article and discovered that my wife had brought a decorate wreath into the house that included California Bay Laurel Leaves two weeks ago when my headaches returned. The wreath has been removed and the constant tingle in my nose is already gone.
I’m surprised little is know about this relationship. I do not suffer from chronic headaches, but discovered the connection a few years back while hiking in the canyons around Los Angeles. I love the smell of bay leaf and often brought it home for cooking. On one such hike, I ground some bay leaf between my fingers to release the aroma, gave it a good sniff and was quite taken aback by the effect; a cool, aromatic sensation, followed by pretty intense pain. The aroma and sensation was particularly acute and highly localized very deep in the sinus. I came across this site while researching the cause of this pain, experienced again today. Hope this helps someone.