Migraine prevention (variable evidence)
Several positive RCTs show feverfew reduces migraine frequency (by 24–32%) and severity — but a Cochrane review of 6 trials found mixed results, with only some preparations showing significant benefit. The inconsistency is largely attributed to variable parthenolide content across commercial products. Standardized parthenolide extracts (MIG-99) show more consistent results than unstandardized products.
Anti-inflammatory activity
Parthenolide inhibits NF-κB by covalently modifying the IκB kinase β subunit — a strong, irreversible anti-inflammatory mechanism also being investigated for cancer applications. This NF-κB inhibition reduces prostaglandin production, inflammatory cytokines, and may contribute to the anti-migraine effects through reduced neuroinflammation.
Platelet aggregation inhibition
Parthenolide inhibits platelet aggregation and reduces serotonin release from platelets — two mechanisms historically proposed to explain feverfew's anti-migraine effects, as platelet serotonin release is elevated before migraines and contributes to vasomotor changes initiating the migraine cascade.
Parthenolide NF-κB covalent inhibition
Parthenolide contains an alpha-methylene-gamma-lactone moiety that covalently alkylates cysteine 179 of IKKβ — irreversibly inhibiting IκB kinase and NF-κB activation. This strong, sustained NF-κB blockade reduces expression of inflammatory genes including COX-2, TNF-α, and IL-6 in neuronal and immune cells.
Serotonin release inhibition from platelets
Parthenolide inhibits serotonin secretion from platelets by blocking secretory arachidonate metabolism and prostaglandin-thromboxane synthesis. Since platelet serotonin release before migraines contributes to vasomotor dysregulation, this mechanism was the original rationale for feverfew in migraine prevention.
Neutrophil degranulation inhibition
Feverfew extracts inhibit neutrophil degranulation and chemotaxis — reducing the release of inflammatory proteases and reactive oxygen species that contribute to neurogenic inflammation in migraine and inflammatory conditions.
Randomized, double-blind, placebo-controlled trial of MIG-99 feverfew extract (6.25 mg three times daily) vs. placebo in 147 migraine patients for 16 weeks.
147 migraine patients. 16-week prevention trial.
MIG-99 significantly reduced migraine frequency by 24% vs. placebo in the subgroup with ≥4 migraines at baseline. Migraine severity also improved. Non-standardized feverfew products showed inconsistent results, highlighting the importance of parthenolide standardization.