How (And Why) to Use Semicolons

Ah, the semicolon. Part comma, part colon, 100% confusing. Do you remember how to use them, and do you even need to? In many cases, semicolons are a personal preference—a way to link sentences together without using a conjunction like “and,” “or,” or “but.” They can also help clarify long lists of items that might otherwise run together. What a useful little tool!

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Semicolons are most commonly used to join two sentences together that share a common thought but aren’t linked with a conjunction.

EM board review is exhausting; I’m going to fall asleep soon.

These two sentences are separate but related—they both deal with being exhausted. (If you can relate to this sentence, go outside! Take a nap! Eat a snack!) We technically could separate these thoughts with a period, but that would lead to hard stop, causing two stilted sentences: “EM board review is exhausting.” Full stop. Then, “I’m going to fall asleep soon.” There are plenty of ways my original sentence could be punctuated to avoid a semicolon. Here’s one:

EM board review is exhausting, and I’m going to fall asleep soon.

It all comes down to personal preference.

A helpful thing that semicolons can do is clarify long lists. Commas aren’t always the clearest way to separate items, especially when we have extra punctuation. If some of the items contain their own commas, using semicolons between the list items (instead of more commas) keeps everything much clearer.

Confusing? Here’s an example:

High-risk conditions include hypertension, cardiac surgery or catheterization for coronary or valvular disease, aortic coarctation, inflammatory diseases that cause vasculitis such as giant cell arteritis, Takayasu arteritis, rheumatoid arthritis, and syphilitic aortitis, and pregnancy and delivery.

Take a look at “inflammatory diseases that cause vasculitis such as giant cell arteritis.” When we first read through the list, we might assume that giant cell arteritis is one example of this type of inflammatory disease. But then we get to Takayasu arteritis, rheumatoid arthritis, and syphilitic aortitis. Are those also examples of inflammatory diseases that cause vasculitis, rather than separate high-risk conditions? Yes? Let’s swap in some semicolons to make things extra clear:

High-risk conditions include hypertension; cardiac surgery or catheterization for coronary or valvular disease; aortic coarctation; inflammatory diseases that cause vasculitis such as giant cell arteritis, Takayasu arteritis, rheumatoid arthritis, and syphilitic aortitis; and pregnancy and delivery.

Now it’s clear that each high-risk condition is separated out by semicolons, and any punctuation within those semicolons belongs to the individual high-risk condition. If there isn’t any punctuation within your list items, use commas as usual.

Make sense? Am I making things worse? If you want to avoid semicolons at all costs, try reordering your sentence (if the content still flows well) to put the extra commas last:

High-risk conditions include hypertension, cardiac surgery or catheterization for coronary or valvular disease, aortic coarctation, pregnancy and delivery, and inflammatory diseases that cause vasculitis such as giant cell arteritis, Takayasu arteritis, rheumatoid arthritis, and syphilitic aortitis.

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