Filipendula ulmaria, commonly known as Meadowsweet or Mead Wort in English, and as Mädesüß in German, is a perennial herb in the family Rosaceae (the family of apples and roses), and grows in damp meadows. It is native throughout most of Europe and Western Asia (Near east and Middle east). It has been introduced and naturalized in North America. The botanical name 'ulmaria' means 'elmlike', in reference to its individual leaves which resemble those of the elm tree (Ulmus). Like slippery elm bark bark, Meadowsweet contains salicylic acid, which has long been used as a painkiller. In 1897, Felix Hoffmann created a synthetically altered version of salicin, derived from Meadowsweet, which caused less digestive upset than pure salicylic acid. The new drug, acetylsalicylic acid, was named 'aspirin' by Hoffmann's employer Bayer AG after the old botanical name for meadowsweet, Spiraea ulmaria.
In short, by eating 1 or 2 fresh raw Meadowsweet / Mädesüß leaves, your headache will go away.
A tea made from Filipendula ulmaria flowers or leaves has been used in traditional Austrian herbal medicine for the treatment of rheumatism, gout, infections, and fever.
If you find Meadowsweet / Mädesüß growing wild you can transplant some to your herb garden, or you can order it from your local nursery.