In the past year I have added a few more which I happily share below. Enjoy!
First up is: "To Cure Rebellion" (graphic of a cannon shell with lit fuse) "This is the pull that will cure or kill." This cover uses medical terminology - pills, cures, remedies, "taking your medicine," and other rhetorical devices - that fits well with both war and (especially) political disagreements, as do many of the medical-related Civil War patriotic covers.
Second - A "Paris Rat" and a "Manchester Rat" eating cotton labeled as "Secession Powder for Rats." At first glance, this might not seem medical-related, but in fact it refers to "rat powders," "insect powders," and other rodent powders that were popular as poisons "back in the day." Collecting vintage poison bottles is an important part of the antique bottle and glass collecting hobby. My good friend, Ferdinand Meyer V at Peachridge Glass, is an expert and avid poison collector. The Paris and Manchester rats would seem to refer to the French and British merchants more interested in maintaining their "hunger" for cotton than in the merits (or lack thereof) of secession and the American Civil War.
Third - The "Black Drop" cover features a caricature of an enslaved African-American "bottled up" with the text: "A popular medicine used by the C.S.A. aristocracy, that cannot be obtained in any Northern apothecary shop, being com-pound-ed exclusively on the sacred soil." The cover features a message sympathetic to abolition while still using unfortunate cartoonish imagery of African-Americans. Stephen Boyd devotes an entire chapter to this subject in his excellent book, Patriotic Envelopes of the Civil War: The Iconography of Union an Confederate Covers (see my review and interview with Dr. Boyd here). As for "Black Drop": this is a reference to an actual medicine! It was composed of opium, vinegar, spices, often with sugar, and went by several proprietary names.
And, finally, my FAVORITE: A clever graphic featuring an envelope of headache powder, a bottle of "Union Bitters," and a package of Dr. Scott's Pills," with the supremely clever poem:
To cure secession and its ills
Take Dr. Scott's Cast Iron Pills
Well mixed with powder of saltpetre
Apply it to each "Fire Eater"
With Union Bitters, mix it clever,
And treason is warned off forever
I know there are more medicine-related covers out there...if you have ideas of what I should be looking for, let me know!