Found this in my research.
“Tanacetum parthenium (feverfew), is a well-known herb for the prophylactic treatment of migraine.” (Pfaffenrath et al., 2002)http://onlinelibrary.wiley.com/doi/10.1046/j.1468-2982.2002.00396.x/abstract
“To assess the effectiveness of feverfew as a prophylactic therapy for migraine, a double-blind placebo controlled cross-over trial was conducted for a period of 4 months. Fifty seven patients who attended an outpatient pain clinic were selected at random and divided into two groups. Both groups were treated with feverfew in the preliminary phase (phase 1), which lasted 2 months. In the second and third phases, which continued for an additional 2 months, a double-blind placebo-controlled cross-over study was conducted.
The results showed that feverfew caused a significant reduction in pain intensity compared with the placebo treatment. Moreover, a profound reduction was recorded concerning the severity of the typical symptoms that are usually linked to migraine attacks, such as vomiting, nausea, sensitivity to noise and sensitivity to light. Transferring the feverfew-treated group to the placebo treatment resulted in an augmentation of the pain intensity as well as an increase in the severity of the linked symptoms. In contrast, shifting the placebo group to feverfew therapy resulted in a reduction of the pain intensity as well as in the severity of the linked symptoms.” (Palevitch, Earon & Carasso, 1997).http://onlinelibrary.wiley.com/doi/10.1002/%28SICI%291099-1573%28199711%2911:7%3C508::AID-PTR153%3E3.0.CO;2-H/abstract