Additional information and estimates are based on the empirical observations of the author over 50 years of experience; this is often but not always noted.
To do a word/phrase search one must use the "Search SHA" boxes found on many of the main SHA web pages, including the Research Resources page (upper right side of that page) which links to this site.The Historic Bottle Website (HBW) has no internal search mechanism so be aware that when running a search one will also get non-HBW response links to other portions of the SHA site.) during the early 1900s, it's primary intent was medicinal though undoubtedly many people who used this very popular product did not have self-medication in mind (American Medical Assoc. In addition, various straight liquors were thought to be therapeutic for various ills - gin for the kidneys, rum as a cure for bronchitis, and Rock and Rye for the symptoms of the common cold (Powers 1998).Whiskey was often labeled as - and sometimes even embossed - "For Medicinal Purposes Only" as early as the mid-19th century - long before National Prohibition took effect in January of 1920 (Wilson & Wilson 1968).To be fair, ethyl alcohol was (and is) one of the better preservatives for products intended for internal consumption or external use.
These examples help point out the vague line that existed between liquor/spirits and medicinal products during the 19th and early 20th centuries.(It should be noted that implementation of this requirement began in late 1934, so some bottles made that year will have the noted embossing.) This regulation was repealed in 1964 giving an effective dating tool of 1935 to the mid 1960s for this diagnostic feature (Munsey 1970).Be aware however that for some years after 1964 liquor could still be found in bottles with this embossing since not all liquor producers switched immediately to new bottles due to the expense of new molds or to deplete an existing supply of bottles (Ferraro 1966).Prohibition makes a very convenient dating transition point for liquor bottles which is not available for other types of bottles.However, there were some machine-made liquor bottles and flasks that most definitely pre-date Prohibition.Additional links to images of similar bottles are also frequently included.