GHS REFERENCE / H-CODES / H303

H303 — May be harmful if swallowed

The GHS hazard statement for acute toxicity, oral, category 5. Here is what it means, the label elements that travel with it, and the substances that carry it.

At a glance

Official statementMay be harmful if swallowed.
Hazard classAcute toxicity, oral
CategoryCategory 5
Signal wordWarning
PictogramNone assigned

What it means

Serious harm — up to and including death — from swallowing a single dose or several doses within 24 hours. Categories 1 (most severe) onward are set from acute toxicity estimates (ATE) per GHS Chapter 3.1.

A UN GHS Category 5 statement. OSHA HazCom 2024 retains acute-toxicity categories 1–4 only, and EU CLP does not use Category 5, so this code does not appear on US- or EU-regime SDSs. Our engine emits it only when classifying under the full UN GHS regime.

Substances that carry H303

None of the 4,225 substances in our database carries H303 in pure form. The note above explains why it is rare on US and EU sheets.

Same hazard class: H300 · H301 · H302

Reference information, not legal or professional advice. Statement texts and allocations follow GHS Rev 9 / 29 CFR 1910.1200 Appendix C as implemented by our classification engine; the regulatory text and agency practice control. Claims last reviewed July 23, 2026.

The engine writes these for you.

When SDS HQ authors an SDS or a container label, it assigns the hazard statements, signal word, pictograms, and precautionary statements from these same tables — automatically, with the calculation shown.

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