Does Tall Man lettering catch wrong words on drug labels?

No. Tall Man lettering capitalizes the letters that differ between look-alike drug names, so it helps with name mix-ups, not ordinary words. A correctly spelled wrong word in a warning or a dosing line, the failure ContextRx documents on FDA DailyMed labels, gets no capital letters. It needs a read for meaning.

What Tall Man lettering is

The FDA defines Tall Man lettering as a technique that uses uppercase lettering to help differentiate look-alike drug names. Starting on the left side of a name, it capitalizes the letters that differ between similar names. The FDA's own examples are pairs of real generic drug names that share many of their letters.

The FDA says Tall Man lettering can be used along with color or bolding to draw attention to the differences and to alert healthcare providers that a name can be confused with another.

Made-up example: two invented names, zorbaTIL and zorbaMEX, with the differing letters in capitals.

Who decides which names get it

The FDA started its Name Differentiation Project in 2001 to continually evaluate postmarketing reports of name pair confusion. The FDA says its evaluation weighs factors including how similar the names are, the safety risks of confusing them, overlapping product characteristics, and reports of wrong drug errors. If the FDA decides Tall Man lettering is appropriate, it asks the manufacturer to voluntarily revise its labels and labeling, then updates its list. The FDA may also use labeling revisions, safety communications and other approaches.

ISMP publishes its own list of look-alike drug names with recommended Tall Man letters. ISMP says it's mostly generic names, with a few brand names. The current ISMP listing, now hosted by ECRI, cites the combined FDA and ISMP lists as ISMP, 2023.

Name confusion vs wrong words

These are different failures:

• Name confusion: two real drug names mistaken for each other.
• Wrong word: a real word in the wrong spot, changing what the sentence says.

Both get past spellcheck. Tall Man lettering targets the first. It doesn't change the ordinary words around the name.

Made-up example: a label prints a name with correct Tall Man letters, and the warning beneath it says "hypertension" where it should say "hypotension". The name is protected and the warning is wrong.

Made-up example: a direction meant to say "oral" reads "aural". No capital letters flag it.

What catches each

Our view:

• For names: Tall Man lettering, color and bolding, as the FDA describes.
• For the words around them: a read for meaning, line by line, with the dosing and warning lines first.

For pairs that trip readers, see confusable words in drug labeling and confusable abbreviations to watch for. For why spellcheck misses both, see does spellcheck catch wrong words on drug labels. For the link to medication errors, see can label wording cause medication errors.

Sources

• FDA Name Differentiation Project
• Look-Alike Drug Names with Recommended Tall Man (Mixed Case) Letters

Last reviewed: October 14, 2026

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What is Tall Man lettering?

It's a technique that uses uppercase letters to highlight the differences between look-alike drug names.

Who decides which drug names get Tall Man letters?

The FDA keeps a list through its Name Differentiation Project and asks manufacturers to revise labels voluntarily. ISMP publishes its own list.

Does Tall Man lettering prevent wrong-word errors?

No. It helps tell look-alike drug names apart. A correctly spelled wrong word elsewhere on the label needs a read for meaning.

Is a look-alike drug name the same as a wrong word?

No. A look-alike name is two real drugs mistaken for each other. A wrong word is a real word that changes what the sentence says.