Butterbur is an effective treatment for migraine headaches that can potentially help with other conditions, such as allergic rhinitis (hay fever) and asthma. Preliminary research suggests It may even protect the brain from oxidative stress. Keep reading to learn more about the benefits of this plant, and why you need to choose the supplement wisely.
What Is Butterbur?
Butterbur (any of the plants of the Petasites genus), also known as coltsfoot, is a flowering plant native to Asia, Europe, and North America. It has been used in traditional medicine for thousands of years to treat a wide range of ailments from high blood pressure (hypertension) and asthma to tumors. It was even used to treat plague and fever during the Middle Ages [1, 2].
There are several types of butterbur, though the most well-studied are Petasites japonicus, also called giant butterbur, and Petasites hybridus. Though related, the two are distinct species and may have different properties.
Petasites japonicus is eaten as a vegetable in Eastern Asia and also used in traditional medicine. Petasites hybridus is native to Europe, where it is not considered a culinary plant but is still used medicinally [3, 4, 5].
Petasites plants have to be processed in the laboratory to ensure they are safe to consume. One of these extracts is referred to as Butterbur Ze339 or Ze339 .
It is most commonly used for migraine and allergy relief and has been the subject of multiple clinical trials suggesting that it is an effective treatment for both conditions, in addition to containing beneficial chemicals that may reduce inflammation, oxidation, and pain [7, 8, 9, 10].
This plant contains:
- Petasins, which may reduce inflammation 
- S-isopetasin, petatwalide B, and bakkenolide B, which may widen blood vessels and decrease inflammation [4, 11, 12]
- Flavonoids, which are antioxidants that may decrease inflammation and fight bacterial infections and cancer 
- Pyrrolizidine alkaloids, which are toxic to the liver and may cause cancer. These can be removed in the laboratory [13, 5]
Mechanism of Action
The anti-inflammatory properties of butterbur are conferred mainly by molecules called petasins, which act to limit the body’s production of inflammatory molecules such as:
- Leukotrienes [9, 14]
- Eosinophil cationic protein (ECP) and TNF-α [15, 16]
- Interleukins IL-2, IL-4, IL-5, IL-6, IL-8 IL-13, and RANTES [17, 18, 19]
- Active STAT molecules [19, 20].
Butterbur may also relieve pain by decreasing the sensitivity of the brain cells that perceive it. Isopetasin decreased the activity of the protein TRPA1, which is found on the surface of sensory neurons, decreasing neuron sensitivity and, thereby, pain [21, 22, 23].
Flavonoids from the leaves of Petasites japonicus activate :
- Nrf2, which controls the production levels of many genes affecting the body’s response to free radical damage. After activation by the flavonoids in butterbur, Nrf2 activates the HO-1 pathway that produces several chemicals including biliverdin, which is a powerful antioxidant [24, 10, 25].
- Heat-shock response transcriptional elements (HSE), that help coordinate the body’s response to stressors including sun damage. UV radiation can cause proteins to unfold and become nonfunctional. HSE activated by butterbur switches on the HSP70 pathway, which ensures proteins maintain their proper shapes [26, 10].
- May prevent migraine attacks
- May help with hay fever and seasonal allergies
- May help with asthma
- May improve somatic symptom disorder
- Insufficient evidence for some benefits
- Extracts with pyrrolizidine alkaloids may cause liver damage and cancer
- Not safe for pregnant women
- May cause allergies
The most common use of butterbur is for the relief and prevention of migraines and headaches.
In a study of 33 adults, butterbur extract decreased the average number of migraine attacks per month after 3 months of treatment. Overall, 45% of individuals treated with butterbur showed improvement compared to placebo .
Another study compared 245 adults over 4 months. There was a 48% decrease in migraine frequency in the group given butterbur extract, compared to 26% for the placebo group. In total, 68% of patients who received 75 mg butterbur reported improvement .
In a survey of 108 children aged 6 to 17, the rate of reported migraine attacks decreased by at least 50% in 77% of children. The study found that, after 4 months of treatment with butterbur, 91% of patients felt “substantially” or “at least slightly improved” .
In a small trial on 58 primary school children with migraine, butterbur root extract failed to prevent migraines during the 12-week treatment but was effective during an 8-week follow-up period. However, music therapy was more effective in both time periods .
Butterbur root extract is currently recommended for short-term use by both the Canadian Headache Society and the American Headache Society for short-term prevention and treatment of migraine headaches [31, 32].
All in all, the existing evidence supports the common use of butterbur in preventing migraine attacks. You may discuss with your doctor if it may be helpful in your case. Importantly, never use butterbur in place of what your doctor recommends or prescribes.
2) Hay Fever and Seasonal Allergies
Multiple studies have found butterbur effective at relieving seasonal allergy symptoms.
In a survey of 580 people who took the extract for two weeks, 90% reported a reduction in seasonal allergy symptoms .
A study involving 186 patients with allergic rhinitis (hay fever) showed that butterbur extract (Ze339) decreased symptoms after just one week of treatment .
Another study involving 20 individuals reported that after two weeks of treatment with butterbur extract, patients had improved recovery time upon allergen exposure .
Two further studies, with a combined total of 346 patients, showed that butterbur (Ze339) was as effective as fexofenadine (Allegra) and cetirizine (Zyrtec) in reducing seasonal allergy symptoms. Both are antihistaminic drugs used to treat allergies [35, 36, 37].
Animal models showed that these effects are caused by a reduction in eosinophils (types of white blood cells) and leukotrienes in nasal tissue as well as a reduction in histamine, which contributes to the development of allergy symptoms [38, 39].
Though the majority of studies have used the Petasites hybridus variety of butterbur, one study suggests that Petasites japonicus is also effective in treating seasonal allergies .
Despite a large amount of promising research, there is some conflicting evidence. In a study of 35 patients, butterbur failed to improve hay fever symptoms, conflicting with other reports .
Again, the evidence suggests that butterbur may help with hay fever and seasonal allergies. You may use it as a complementary approach if your doctor determines that it may help improve your condition.
Several studies have found butterbur effective at reducing asthma symptoms.
In a study involving 64 adults and 16 adolescents, who were given butterbur extract (Petasites hybridus) in addition to their normal asthma medication, 83% of patients showed an improvement in their symptoms .
In another study of 16 asthmatic patients, a combination of butterbur and inhaled corticosteroids showed reduced inflammation symptoms compared to treatment with corticosteroids alone .
Similar results were obtained in studies in mice, which showed that, when given butterbur and then subjected to allergens, mice had decreased inflammation in the lungs, reduced recruitment of immune cells to the inflamed areas, and reduced mucus secretion [17, 18].
Butterbur contains multiple compounds that contribute to the relief of asthma symptoms. S-iso-petasin may be acting as a bronchodilator, while petatewalide B and bakkenolide B reduce eosinophils, macrophages, and lymphocytes (all types of white blood cells) in the bronchial fluid [4, 11, 12].
Although the results are promising, two clinical trials and some animal and cell-based research cannot be considered sufficient evidence to back this potential benefit of butterbur. More clinical trials on larger populations are required.
2) Somatic Symptom Disorder
Somatic symptom (somatoform) disorders are a group of psychological disorders in which a patient experiences physical symptoms that can’t be explained by any underlying medical condition.
A study of 182 people with somatoform disorders reported that a combination of the herbs butterbur root, valerian root, passionflower herb, and lemon balm leaf significantly improved measures of anxiety and depression after two weeks of treatment. The same combination without butterbur was significantly less effective .
A single clinical trial testing butterbur in combination with other herbal extracts is clearly insufficient to claim that this herb may help with somatic symptom disorder. Further clinical research testing butterbur alone is needed.
Animal and Cell Research (Lack of Evidence)
No clinical evidence supports the use of butterbur for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies should not be interpreted as supportive of any health benefit.
Butterbur extracts (Petasites japonicus) prevented the death of neurons in the brains of mice due to kainic acid, which mimics the effects of free radical damage to the brain. In addition to reducing brain cell death, the mice also had fewer seizures [44, 45].
In a cell-based study, butterbur extract protected human nerve cells from damage and death caused by reactive oxygen species (ROS) .
Butterbur extract (Petasites hybridus) reduced the size of stomach ulcers in mice and protected against stomach damage caused by alcohol .
Blood Cholesterol Levels
Butterbur extract significantly decreased the total and LDL-cholesterol levels in mice .
An extract of Petasites japonicus reduced fat accumulation and prevented overall weight gain in obesity-prone mice .
High Blood Pressure
S-petasin and iso-S-petasin, active compounds in butterbur, decrease blood pressure in rats. These compounds, decreased the activation of the smooth muscles surrounding the blood vessels, causing them to widen and, thereby, reduced blood pressure [49, 50, 51].
Although butterbur naturally contains molecules that cause liver damage, processed butterbur without these molecules actually increased the activity of antioxidant enzymes in the liver in mice.
Specifically, the enzymes which showed increased activity were glutathione reductase (GSR), glutathione peroxidase (GPx), glutathione S-transferase (GSTs), and quinone reductase (QR). These enzymes protect the liver from free radical damage [52, 48].
In a mouse cell-based study, an extract of butterbur (Petasites japonicus) stimulated the growth of cells that produce sperm in test tubes .
Preventing Blood Clots
Petasites japonicus contains a type of enzyme called fibrolytic serine protease, which helps the proteins that form blood clots (fibrigins and fibrinogens) dissolve in the blood, preventing the blood clot from growing large. This enzyme has been shown to prevent blood clots (thrombosis) in mice and to promote the breakdown of human fibrins and fibrinogens [54, 55].
An extract from the leaves of butterbur (Petasites japonicus) reduced the size of liver tumors in mice and was toxic to stomach, colon, and uterus cancer cells [56, 57].
Side Effects & Precautions
This list does not cover all possible side effects. Contact your doctor or pharmacist if you notice any other side effects.
Call your doctor for medical advice about side effects. In the US, you may report side effects to the FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada, you may report side effects to Health Canada at 1-866-234-2345.
The most commonly reported side effects of butterbur supplements were gut-related, including belching, diarrhea, and nausea .
Other less common side effects have been reported as well [41, 28, 29, 30]:
- Allergic conjunctivitis
- Allergic rhinitis
- Difficulty exhaling or difficulty breathing
- Dermal/allergic symptoms
- Itchy eyes
- Hair loss
- Reversible cholestatic hepatitis
- Severe nausea
- Severe depression
- Skin discoloration
- Stomach pain or flatulence
- Stool discoloration
Liver toxicity and increased liver enzyme production are also possible [6, 37].
Unprocessed Butterbur Is Toxic to the Liver
Raw, unprocessed butterbur contains harmful substances called pyrrolizidine alkaloids (PA), which cause liver damage and may even cause cancer [5, 58].
For this reason, it is important to choose butterbur supplements that have been produced by a reputable manufacturer. The products are typically labeled “PA-free.”
Little is known about the effects of butterbur on pregnancy. Due to the risk of accidental contamination with pyrrolizidine alkaloids, pregnant or breastfeeding women should avoid butterbur.
Potential for Allergies
People with allergies to Compositae or Asteraceae plants (such as ragweed, daisies, and chrysanthemums) may also be allergic to butterbur as it belongs to this plant family.
When taking butterbur products, there is a risk of liver damage, so people with a compromised liver function should avoid them.
Several of the benefits have been studied in animals, but it is unknown whether butterbur would have the same effect in humans.
Also, the safety of the long-term use of butterbur has not been established.
There are a number of butterbur supplements on the market. They have not been approved by the FDA for medical use due to the lack of solid clinical research. Regulations set manufacturing standards for supplements but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing with butterbur.
Butterbur leaf extracts that have undergone clinical trials include Petadolex and Tesalin-N (Butterbur Ze339) [7, 6].
Because butterbur is not approved by the FDA for any condition, there is no official dose. Users and supplement manufacturers have established unofficial doses based on trial and error. Discuss with your doctor if butterbur may be useful as a complementary approach in your case and which dose you should take.
Reduction in migraine headache symptoms was achieved with 25 to 75 mg of extract taken daily for 3 to 4 months [27, 28].
Approximately 2 to 3 doses of 8 mg per day of butterbur extract were effective in the treatment of allergic rhinitis symptoms, taken for a period of 2 weeks [8, 33].
Recommended dosages for other uses have not been established.
The opinions expressed in this section are solely those of butterbur users, who may or may not have medical or scientific training. Their reviews do not represent the opinions of SelfHacked. SelfHacked does not endorse any specific product, service, or treatment.
Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare providers because of something you have read on SelfHacked. We understand that reading individual, real-life experiences can be a helpful resource, but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified healthcare provider.
Most users took in butterbur supplements to prevent migraines and other headaches. Several of them were satisfied and reported noticing days with no headaches and fewer and less severe migraines after few weeks. However, some users taking it for this purpose reported not noticing any change.
A few people used butterbur for swollen sinuses, often reporting good results.
Whether they were satisfied or not with the results, several users were concerned about the risk of liver damage.