Medicus Incomprehensibilis – Writing in Plain English


Oscar Linares, David Daly, and Gertrude Daly


Image Credit: ‘Sign Here’ by Helloquence CC0 Public Domain via Unsplash.


Since writing is the only means the medical profession has of universally disseminating knowledge concerning new therapeutic concepts, medical discoveries, or clinical experience, it is the moral obligation of every physician who has made an original scientific observation or has formulated from his own experience a new medical theory, to publish it for the information of his colleagues, and the ultimate benefit of mankind. – Selma DeBakey (1).


Open any leading medical journal today and you’ll find an article that shows symptoms of medicus incomprehensibilis. Medicus incomprehensibilis is a condition which affects doctors and other medical scientists, causing them to write dull, lifeless prose that is hard to understand. The condition has two causes: necessary scientific complexity and needless grammatical complexity. The treatment involves cutting needless grammatical complexity, using proven plain-English writing tips, while keeping essential scientific content.

Medicus incomprehensibilis wastes time for every reader, reduces understanding, and slows the spread of new medical knowledge (read this freely available chapter). It conveys the scientific message less clearly, vividly, and memorably. It keeps some readers from fully understanding. It causes others to give up, since reading becomes too tedious. It excludes any potential reader who might understand the science, but can’t deal with the complex writing style. This prevents medical discoveries from reaching the widest reasonable audience. The widest reasonable audience includes anybody with an interest in science, including people from other countries, and people in other specialities, sub-specialities, disciplines, or levels of training. Treating medicus incomprehensibilis saves time for every reader and improves understanding, thus speeding the spread of new medical knowledge.


This matters in the 21st century, as English is the global language of science. English-language medical journals contain discoveries from doctors and other medical scientists from around the world. Yet three out of four English users are not native speakers. Thus, it makes sense to write about complex science without using complex grammar.

Medical science writing is important and writing in plain English is a skill honed by practice. It is every medical writer’s duty to write clearly and concisely. Learning to express complex ideas clearly and concisely is in no way a remedial skill. Rather, it can only be seen as a sign of mastery.



1. DeBakey S, “Suggestion on Preparation of Medical Papers”, JAMA 155, no,18 (1954): 1573.

Oscar Linares, MD is a Cuban-born internist and geriatrician (now retired). He studied mathematical modelling under Dr. Loren Zech, a senior scientist at the National Institutes of Health. He is an experienced medical researcher and author of over 40 peer-reviewed scientific articles.

David Daly is a retired lawyer experienced in drafting and negotiating international automotive contracts in plain English. He has won three awards from the State Bar of Michigan for clear legal writing. He has worked with Dr. Linares to write medical articles, medical opinions, and legal briefs in medical cases in plain English.

Gertrude Daly
is a technical writer and editor.

Oscar, David, and Gertrude are the authors of Plain English for Doctors and Other Medical Scientists (OUP, 2017).

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