Caution (triangle with exclamation mark)
The standard’s wording, as the sources below reproduce it:
“To indicate that caution is necessary when operating the device or control close to where the symbol is placed, or to indicate that the current situation needs operator awareness or operator action in order to avoid undesirable consequences.”
ISO 15223-1:2021, 5.4.4 · ISO 7000-0434A
What it means for you
There is a warning or precaution you need to know before use, and it is not printed next to the symbol. Older glossaries (Cook, Stago) give the earlier wording: consult the instructions for use for important cautionary information that cannot be presented on the device itself.
Whether a device is right for you is a question for your pharmacist, nurse or doctor.
- What it looks like
- An outline triangle, point up, with an exclamation mark inside. Stago notes it is sometimes printed on a yellow background.
- Where you see it
- Device labels, battery compartments, tubing connectors and the boxes of devices whose instructions carry warnings.
- Other names
- attention; warning triangle; see instructions for warnings
What it does not tell you
It does not say what the hazard is. The instructions for use do.
Often confused with
Indicates that there are potential biological risks associated with the medical device.
More symbols in “A triangle”
Sources
ISO 15223-1 is a paid standard, so the wording above is quoted as 3 publishers’ public documents reproduce it. Each was fetched and read on the date shown:
- Boston Scientific: Symbols Glossary — ISO 15223-1 5.4.4 “Caution — To indicate that caution is necessary when operating the device or control close to where the symbol is placed, or to indicate that the current situation needs operator awareness or operator action in order to avoid undesirable consequences.” Image labelled ISO 7000-0434A. Checked 2026-09-25.
- NE Scientific: Master Symbol Glossary (CTF-100011 Rev 01) — Shows the outline triangle with ! for reference no. 5.4.4 (ISO 7000-0434A), with the same wording. Checked 2026-09-25.
- Stago: Glossary of symbols (520233-A_EN) — “Caution — Indicates the need for the user to consult the instructions for use for important cautionary information such as warnings and precautions that cannot … be presented on the medical device itself. Sometimes used with a yellow background.” Checked 2026-09-25.
Plain-language parts are in our own words; quotations are the sources’ wording.