St. Jacobs Oil, Limited, of London, registered two Trade Marks (#59,520, #59,520) in 1907. The Trade Marks were for a "Hair Renewer, Restorative, and Tonic for the Hair, Scalp & Skin." They said they had been using the brand names since 1881.
The two Trade Marks were for "Kletten Wurtzel Oel," and "Burdock Root Oil." As far as I can tell, they were German and English versions of the same product name.
According to Fike, the product "St Jacob's Oil" was originated by Charles A. Vogeler & Co., of Baltimore, and around 1900 it was bought by the English firm. I've seen advertisements indicating that St Jacob's Oil was for pain. Most likely, the primary product they sold was this pain killing liniment. "Vogeler's Kletten Wurzel (Burdock) Oil" was for sale in the 1880 Morrison & Plummer catalog.