 In 1897 chemists working at Bayer AG produced a synthetically altered version of salicin, derived from the species Filipendula ulmaria (meadowsweet), which caused less digestive upset than pure salicylic acid. The identity of the lead chemist on this project is a matter of controversy. Bayer states the work was done by chemists Heinrich Dreser and Felix Hoffmann, but Jewish chemist Arthur Eichengrün later claimed he was the lead investigator and records of his contribution were expunged under the anti-Semitic Nazi regime. The new drug, formally acetylsalicylic acid, was named Aspirin by Bayer AG after the original botanical name for meadowsweet, Spiraea ulmaria, derived from "acetyl" and Spirsäure, an old German name for salicylic acid derived from the Latin Spiraea ulmaria. By 1899, Bayer was selling it around the world. The popularity of aspirin grew over the first half of the 20th century, spurred by its supposed effectiveness in the wake of the Spanish flu pandemic of 1918. However, recent research suggests that the high death toll of the 1918 flu may have been partly due to aspirin, though this is controversial and not universally accepted. This theory gained support when a recent repetition of the 1918 flu outbreak, with the same virus, had a low fatality rate. Aspirin's profitability led to fierce competition and the proliferation of aspirin brands and products, especially after the American patent held by Bayer expired in 1917.
