Bayer Co. v. United Drug Co.

Bayer (plaintiff) manufactured acetylsalicylic acid under the trademark 'Aspirin' and initially sold it only to manufacturing chemists, physicians, and retail pharmacies, all of whom knew Bayer was the source; the drug reached the general public only by prescription during this period. Starting in 1904, Bayer began selling tablets directly to consumers under the 'Aspirin' label, but without Bayer's own name on the bottles until 1915, two years before its patent expired. Once the patent expired, United Drug (defendant) began selling its own acetylsalicylic acid as 'Aspirin,' and Bayer sued for common-law trademark infringement.