Quote Origin: Be Careful About Reading Medical Books. You May Die of a Misprint
Mark Twain? Oliver Wendell Holmes Sr.? Markus Herz? Ernst Freiherr von Feuchtersleben? Walter C. Alvarez? Anonymous?
Question for Quote Investigator: All kinds of medical advice is available on the internet. However, the quality is variable, and some of the recommendations are deleterious. A pertinent quip has been circulating for decades. Here are two versions:
(1) Never read medical books. You might die of a misprint.
(2) Be careful when you’re reading health books. You may die of a misprint.
This remark has been attributed to the famous humorist Mark Twain and the prominent U.S. physician Oliver Wendell Holmes Sr., but I have not found any solid citations. Would you please explore this topic?
Reply from Quote Investigator: The earliest match located by QI appeared in the German periodical “Der Gesellschafter oder Blätter für Geist und Herz” (“The Companion or Pages for Mind and Heart”) in 1817. The following excerpts in German are followed by translations into English. Boldface added to excerpts by QI:¹
Zu einem Patienten, dem es zur Gewohnheit geworden war: durch medizinische Hülfsbücher sich selbst helfen zu wollen, sagte der verstorbene Dr. Herz: Nehmen Sie sich in Acht, Sie sterben einmal an einem Druckfehler!
The late Dr. Herz said to a patient who had become accustomed to trying to cure himself with medical manuals: “Be careful, you’re going to die one day from a printing error!”
In 1818 the full name of the doctor was specified as Marcus Herz in a short item printed in “Die Leuchte: Ein Zeitblatt für Wissenschaft, Kunst und Leben” (“The Lamp: A Journal for Science, Art and Life”):²
„Der stirbt noch an einem Druckfehler!” sagte Marcus Herz von einem, der sich aus Büchern kurirte.
“This one is going to die of a misprint!” said Marcus Herz of one who cured himself from books.
Markus Herz (also spelled Marcus Herz) was a prominent German physician and lecturer who died in 1803. Thus, these attributions occurred posthumously which reduced their credibility. Nevertheless, Markus Herz is the leading candidate for creator of this quip.
Oliver Wendell Holmes Sr. who died in 1894 received credit for the joke by 1939. Mark Twain who died in 1910 received credit by 1972. In both cases, this evidence is weak.
Below are additional selected citations in chronological order.
In 1838 prominent Austrian physician Ernst Freiherr von Feuchtersleben published “Zur Diätetik der Seele” (“The Dietetics of the Soul”) which included a chapter about hypochondria. Von Feuchtersleben attributed the joke to Herz:³
. . . das sind jene freiwilligen Candidaten der Medizin, die sich in die ganze Krankheitslehre hinein lesen, die sich aus Büchern Recepte verschreiben; zu deren Einem Marcus Herz, der berühmt gewordene Feind alles Schwindels, einmal sagte: Lieber Freund! Sie werden noch einmal an einem Druckfehler sterben!
. . . they are those voluntary candidates of medicine, who read their way into the entire scholarship on diseases, who prescribe themselves recipes out of books: to one of whom Marcus Herz, the famous enemy of all fraud, once said: Dear Friend! One day you are going to die of a printing error!
In 1852 an English translation of Von Feuchtersleben’s book was published in London. Thus, the quip began to circulate in England:⁴
These men become volunteers in the ranks of medicine; they overload their minds with whole courses of physic; they copy prescriptions from printed formulae; and it was to one of this class that Marcus Herz once wittily remarked, “My dear friend, an error of the press will assuredly, some day or other, be the death of you.”
In 1910 Gustav Pollak published “The Hygiene of the Soul: The Memoir of a Physician and Philosopher” based on the life and works of Ernst Freiherr von Feuchtersleben. Pollak reprinted a version of the joke:⁵
Does not the hypochondriac die daily from fear of death? Nothing is more pathetically ludicrous than to see these petty unfortunates who ransack medical books in order to copy prescriptions and rules for the preservation of health. To one of these Dr. Herz once said: “My dear fellow, you will some day die of a misprint.”
In November 1910 the “New-York Tribune” published a version of the joke while acknowledging a German anecdote collection:⁶
A book of anecdotes of famous physicians by Gustav Hochstetter and Georg Zehden has been issued in Berlin. Dr. Marcus Herz Is credited with saying to a patient who read medical books diligently in order to prescribe for himself: “Be careful, my friend. Some fine day you’ll die of a misprint.”
In 1920 the New York humor periodical “Life” printed the following item:⁷
“I doctor myself by the aid of medical books.”
“Yes, and some day you’ll die of a misprint!”
— Boston Transcript
In 1939 Dr. Walter C. Alvarez of the Mayo Clinic in Rochester, Minnesota delivered a speech to his colleagues at the New York Academy of Medicine. He credited the quip to Dr. Oliver Wendell Holmes Sr.:⁸
Dr. Alvarez recalled a story about the reaction of Dr. Oliver Wendell Holmes when he found one of his patients reading a medical book in a Boston library. Dr. Holmes according to Dr. Alvarez, tapped the man on the shoulder and remarked: “You had better not do that old fellow, or someday you’ll die of a misprint.”
In 1957 Dr. W. W. Bauer who was the Director of Health Education for the American Medical Association credited Holmes:⁹
Oliver Wendell Holmes once cautioned a reader whom he found immersed in a home doctor book. “Be careful, or you may die of a misprint.” His advice applies to reading of medical articles, lest you be disappointed by your own misreading.
In 1972 syndicated columnist Stan Delaplane tentatively attributed the jest to Mark Twain:¹⁰
“Be careful about reading medical books. You might die of a misprint.” Who said that? Mark Twain I think.
In 1978 Stan Delaplane revisited the topic, and he credited Twain with a different phrasing for the joke:¹¹
“Never read medical books,” said Mark Twain. “You might die of a misprint.”
In 1987 the compilation “The Wit & Wisdom of Mark Twain” edited by Alex Ayres included the following entry:¹²
“Be careful about reading health books,” warned Mark Twain. “You may die of a misprint.”
In conclusion, the earliest citations in 1817 and 1818 point to Markus Herz as the creator of this quip. He died in 1803; hence, some uncertainty remains about this ascription. Oliver Wendell Holmes Sr. and Mark Twain were born many years after the joke entered circulation. Also, the citations for Holmes and Twain appeared many years after their deaths.
Image Notes: Portrait of The Apothecary by Gabriël Metsu circa 1651–67. This public domain image has been resized.
Acknowledgements: Thanks to Ken Hirsch who posted about this topic back in 2010 on the mailing list of the American Dialect Society. Hirsch located a crucial citation crediting Markus Herz in 1841 together with other helpful citations which he shared via the Mark Twain Wikiquote Talk webpage. Also, thanks to researcher Barry Popik who explored this topic and posted his results in 2012. Popik shared excellent citations for Herz, Holmes, and Twain. Further, thanks to Fred Shapiro whose benchmark reference “The New Yale Book of Quotations” contains the 1841 citation.
Special thanks to Chris Waigl, Dan Goncharoff, and Amy West who provided advice regarding the German to English translations. Additional thanks to Google and DeepL for their translation systems. All errors are the responsibility of the Quote Investigator.
 1817 October 18, Periodical: Der Gesellschafter oder Blätter für Geist und Herz (The Companion or Pages for Mind and Heart), Article: Der Schluß folgt (The ending follows), Quote Page 683, Column 2, Publisher: In der Maurerschen Buchhandlung, Berlin, Germany. (Google Books Full View) link
 1818 May 27, Periodical: Die Leuchte: ein Zeitblatt für Wissenschaft, Kunst und Leben (The Lamp: A Journal for Science, Art and Life), Section: Allerlei aus Abu Taleb’s Miscellanenhefte (All Sorts of Things from Abu Taleb’s Miscellaneous Notebooks), Quote Page 167, Column 2, Publication: Berlin, Germany. (Google Books Full View) link
 1838, Book Title: Zur Diätetik der Seele (The Dietetics of the Soul), Author: Ernst Freiherr v. Feuchtersleben, Quote Page 95, Publisher: Verlag von Carl Armbruster, Wien (Vienna, Austria), (Google Books Full View) link
 1852, The Dietetics of the Soul by Ernest von Feuchtersleben M.D., Seventh Edition, Chapter 10: Hypochondriasis, Quote Page 127, John Churchill, London. (Google Books Full View) link
 1910, The Hygiene of the Soul: The Memoir of a Physician and Philosopher by Gustav Pollak, Chapter 8, Quote Page 101, Dodd, Mead and Company, New York. (Google Books Full View) link
 1910 November 3, New-York Tribune, The Talk of the Day, Quote Page 6, Column 4, New York, New York. (Newspapers_com)
 1920 June 17, Life, Volume 75, Number 1963, Our Foolish Contemporaries, The Danger, Quote Page 1140, Column 1, Life Publishing Company, New York. (Google Books Full View) link
 1939 February 1, The Montreal Daily Star, Too Many “Lab” Tests In Medicine Condemned, (Star Special), Quote Page 31, Column 4, Montreal, Quebec, Canada. (Newspapers_com)
 1957 August 6, The San Francisco Examiner, Health For Today: Analyzing New Discoveries by W. W. Bauer M.D. (Director of Health Education of American Medical Association), Section 2, Quote Page 2, Column 4, San Francisco, California. (Newspapers_com)
 1972 October 26, The Lincoln Star, Postcard by Stan Delaplane, Quote Page 6, Column 4, Lincoln, Nebraska. (Newspapers_com)
 1978 July 20, The Lincoln Star, Writer keeps doctors busy with symptoms from Today’s Health by Stan Delaplane, Quote Page 9, Column 4, Lincoln, Nebraska. (Newspapers_com)
 1987, The Wit & Wisdom of Mark Twain, Edited by Alex Ayres, Topic: Health, Quote Page 97, Harper & Row, New York. (Verified on paper)