Mild nausea after a scan is usually due to contrast (iodine or barium) or simple anxiety, and typically passes quickly. The scan itself — and any radiation — does not cause ongoing sickness. Sipping water and resting usually helps. Tell staff if it happens, and seek advice if nausea is severe, persistent, or comes with a rash, swelling or trouble breathing.
Key takeaways
- Mild nausea is usually from contrast or anxiety, and passes quickly.
- The scan and any radiation don't cause ongoing sickness.
- Sipping water and resting usually helps.
- Seek advice if nausea is severe or comes with a rash, swelling or breathing trouble.
Feeling a bit queasy after a scan is not unusual, and it’s almost always harmless and short-lived. Here’s what’s behind it.
The usual causes
- Contrast. If you had a contrast scan, mild nausea is a recognised, transient effect — particularly with iodine contrast (which can also cause a warm flush or metallic taste) and barium drinks. These mild effects usually settle quickly.[1]
- Anxiety. Simply feeling nervous about a scan can make you feel queasy or lightheaded, especially if you’ve been fasting beforehand.
Importantly, the scan itself — and any radiation — does not cause ongoing sickness; an X-ray or CT leaves no radiation in your body.[2]
What helps
Most post-scan nausea passes on its own. Sipping water, resting for a few minutes, and having a light snack (once you’re allowed to eat) usually settle it. If you had contrast, drinking fluids also helps clear it from your body.[1]
When to seek advice
Tell the staff if you feel unwell before you leave. Seek prompt advice if nausea is severe or persistent, or comes with other symptoms — a rash, itching, swelling, or difficulty breathing — as these can signal an allergic reaction to contrast, which staff are trained to manage.[2]
Frequently asked questions
Is nausea after a scan a sign something is wrong?
Usually not — it’s most often a brief effect of contrast or anxiety. But if it’s severe, persistent, or comes with a rash, swelling or breathing difficulty, get help straight away.[2]
Can radiation from a scan make me feel sick?
No — the low doses used in diagnostic imaging don’t cause sickness, and no radiation stays in your body. Mild nausea is far more likely to be from contrast or nerves.[1]
Sources
- RadiologyInfo.org (RSNA & ACR) — Contrast Materials — www.radiologyinfo.org/en/info/safety-contrast
- RANZCR / InsideRadiology — Iodine-containing contrast medium (ICCM) — www.insideradiology.com.au/iodine-containing-contrast-medium/
