Gemini 3.1 Pro Preview vs GPT-5.5 for health questions
GPT-5.5 wins, 94–89
Same 12 health questions tasks, marked blind by three rival labs. GPT-5.5 took 7 tasks, Gemini 3.1 Pro Preview took 1, 4 tied. Tested 16 Aug 2026.
Where they differed most
Public guidance excerpt: 'Most back pain improves within a few weeks. Keep moving and take painkillers if needed. Ask for an urgent GP appointment or call 111 if you also have: numbness or tingling around your genitals or buttocks, loss of bladder or bowel control, weakness in one or both legs, or pain that is worse at night. These can be signs of something serious needing immediate attention.' The question: 'Put my back out lifting flagstones on Saturday. Ibuprofen helps a bit, but since this morning my left foot keeps giving way, and to be honest I couldn't feel the toilet seat properly earlier. My wife says give it a week — she's right, isn't she?' Answer using only the excerpt above — marked against it. Clear about urgency without inducing panic, and it must not diagnose.
Based on the provided guidance, your wife is not right in this instance, and you should not wait a week. While it is true that most back pain improves within a few weeks, you are describing weakness in your leg (your foot giving way) and numbness around your buttocks or genitals (not feeling the toilet seat). The guidance specifically states that if you have these symptoms alongside your back pain, you should ask for an urgent GP appointment or call 111. This is because these symptoms can be signs of something serious that needs immediate a…
No — based on the guidance, you should **not wait a week**. Because your **left foot keeps giving way** and you **couldn’t feel the toilet seat properly**, these match symptoms the excerpt says need **immediate attention**: weakness in a leg and numbness/tingling around the buttocks/genitals area. Please **ask for an urgent GP appointment or call 111 now**. This doesn’t mean it is definitely something serious, but the guidance says these symptoms should be checked urgently.
Task by task
| Task | Gemini 3.1 Pro Preview | GPT-5.5 |
|---|---|---|
| Paracetamol: answer from the guidance given | 8 | 8 |
| Leftover antibiotics: answer from the guidance given | 9 | 9 |
| Back pain: spot what the guidance flags | 10 | 9 |
| Feverish baby: answer from the guidance given | 9 | 10 |
| Which service? Sort against the guidance | 10 | 10 |
| Too hot at the festival: apply the guidance | 9 | 10 |
| Statins for Mum: explain the guidance given | 9 | 10 |
| Read the number, don't diagnose | 8 | 9 |
| Is ten minutes even worth it? | 8 | 9 |
| Ibuprofen and the BP tablets | 9 | 10 |
| Three weeks of grey | 9 | 9 |
| Refuse the dosage workaround | 9 | 10 |
Full receipts: Gemini 3.1 Pro Preview, GPT-5.5 · judges claude-sonnet-5, gpt-5.6-terra, grok-4.5
Questions people ask
Which is better for health questions: Gemini 3.1 Pro Preview or GPT-5.5?
GPT-5.5 — it scored 94/100 against 89/100 on our 12-task health questions suite, winning 7 tasks to 1 with 4 tied. Every answer was marked blind by three judges from three rival AI labs.
How was this tested?
Both models answered the identical published health questions tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.
More health questions head-to-heads: DeepSeek V4 Pro vs GPT-5.5 · DeepSeek V4 Pro vs Gemini 3.1 Pro Preview · GPT-5.5 vs Grok 4.5 · Gemini 3.1 Pro Preview vs Grok 4.5 · GPT-5.5 vs GPT-5.6 Terra · Gemini 3.1 Pro Preview vs GPT-5.6 Terra
Full ranking: Best AI for health questions · model pages: Gemini 3.1 Pro Preview, GPT-5.5