Butterbur (Petasites hybridus) is a flowering marsh plant that grows across Europe and northern Asia. Its large, umbrella-like leaves historically sheltered butter from summer heat, earning it its common name. The root extract has been used in European folk medicine since at least the Middle Ages to treat fever, plague symptoms, and pain.

The active compounds — petasin and isopetasin — appear to block certain inflammatory signaling molecules (leukotrienes and prostaglandins) that drive migraine pain and allergic reactions. They also seem to relax smooth muscle in blood vessels and airways, which may help reduce the intensity of migraine attacks and ease breathing in allergy sufferers.

Only use standardized, PA-free root extract products — the most studied form is a CO2-extracted product standardized to 7.5–15% petasin. Raw butterbur root, teas made from unprocessed plant material, and any product without a PA-free guarantee should be strictly avoided due to liver toxicity risk.

• Migraine prevention
• Hay fever and seasonal allergies
• Allergic rhinitis (year-round)
• Exercise-induced or allergic asthma
• Headache frequency and severity
• Nasal congestion and sneezing
• Abdominal and bladder spasms
• Itchy, watery eyes from allergies

• Migraine attack frequency (well-supported by clinical trials — daily use shown to reduce attack frequency by roughly 50% in some studies)
• Allergy-season symptom flare-ups (consistent daily use before and during allergy season may reduce peak symptom severity)

Butterbur's active compounds (petasin and isopetasin) are not meaningfully present in any common food — only in the butterbur plant itself. However, an anti-inflammatory diet supports the same pathways butterbur targets. Prioritize oily fish (salmon, mackerel, sardines) for omega-3s that reduce prostaglandins; colorful vegetables rich in quercetin (onions, apples, kale) that naturally calm histamine and leukotriene release; and turmeric and ginger which inhibit similar inflammatory enzymes. Limiting processed vegetable oils (sunflower, corn oil) and sugar can also reduce the underlying inflammatory load that drives both migraines and allergic reactions. If you take butterbur for migraines, reducing caffeine, alcohol, and aged cheeses is also worthwhile as these are common dietary migraine triggers.

• Burping or belching (most commonly reported side effect in trials, usually mild and transient)
• Nausea or stomach upset (especially on an empty stomach)
• Headache or fatigue in early days of use
• Allergic skin reaction (more likely in people with ragweed or daisy family allergies)
• Liver injury risk with non-PA-free or raw preparations — this is serious and not a minor effect

• Recommended daily: 50–75 mg of standardized PA-free extract (standardized to 7.5–15% petasin), taken twice daily (100–150 mg total per day). The most-studied dose in migraine trials is 75 mg twice daily.
• Best time of day: Morning and evening, splitting the daily dose into two equal portions
• With or without food: Always take with food — this meaningfully reduces the likelihood of nausea and burping
• Time to effect: Allergy symptoms: 1–2 weeks; Migraine prevention: 4–12 weeks of consistent daily use
• How long to take it: Clinical trials have studied butterbur for up to 16 weeks continuously. Long-term safety beyond this window is not well established — take breaks of 4–8 weeks every 3–4 months and reassess with a healthcare provider. Do not use continuously for more than 4–6 months without professional guidance.