The health facts most people get wrong.
We've scored more than 10 million answers to Harvard Medical School–reviewed health questions. These are the ones that trip people up the most — and what's actually true. Think you'd do better?
The questions people get most wrong
Ranked by how many people actually missed them. Each percentage is the share of players who picked a wrong answer before getting it right — real questions, real numbers.
- 74%picked a wrong answer first
41,985 playersYou're more likely to get kidney stones if you eat too much of what?
- 64%picked a wrong answer first
29,595 playersWhat's the #1 Thanksgiving cause of death and ER visits?
- 63%picked a wrong answer first
29,545 playersCan't sleep? Which of these can contain hidden caffeine?
- 81%picked a wrong answer first
21,964 playersWhich does the most for your brain as you age?
- 61%picked a wrong answer first
30,344 playersWhen's the best time to eat something sweet to blunt the blood-sugar spike?
- 87%picked a wrong answer first
17,232 playersWhich of these is most likely to raise your cancer risk?
- 90%picked a wrong answer first
15,178 playersDust mites live in your pillow. What should you actually do about it?
- 89%picked a wrong answer first
5,361 playersFor most people, a daily fish-oil supplement…
Based on a snapshot of Quizzify's production data (July 2026): millions of scored plays of Harvard-reviewed quiz questions, ranked by the number of people who missed them. Percentages reflect the share of completed plays in which a player selected a wrong answer before reaching the correct one; each figure here is drawn from thousands of plays. Answers and explanations are the reviewed quiz content.
Where the confusion actually lives
Each tile is a health topic in the Quizzify curriculum, shaded and labelled by the share of players who picked a wrong answer before getting to the right one. Millions of scored plays behind it.
The pattern: people are about 3.4× more likely to be wrong about cancer risk (59.9%) than about their own benefits (18.1%) or how to handle a doctor visit (17.5%). They've learned the paperwork. Nobody ever taught them the medicine.
Twenty-eight more people get wrong
Same rules: real questions, real play counts, real miss rates — ordered by how many people actually got them wrong.
Sun protection
Which sun-protection claim is true?
Reapply after swimming even if it says “waterproof” — and sunscreen does not raise your cancer risk.
77%got it wrong · 32,076 playsExercise
What's wrong with this picture of someone doing sit-ups?
She shouldn't be doing sit-ups in the first place.
73%got it wrong · 26,034 playsHodgepodge
Why is winter “cold-and-flu season”?
Because people are indoors together — not because it's cold.
80%got it wrong · 22,861 playsSummer hazards
Tick-repellent clothing really works. So what's the catch?
Complacency.
74%got it wrong · 23,006 playsSun protection
You're applying the average amount of sunblock. How much more do you need for the SPF on the label?
About three times as much as you're putting on now.
76%got it wrong · 21,956 playsMen's health
Men significantly raise their kidney-stone risk with high doses of which supplement?
Vitamin C.
86%got it wrong · 18,867 playsAging
What's the evidence that gingko biloba improves memory?
There isn't any. No impact.
70%got it wrong · 22,319 playsTeeth & gums
Sugar-free gum…
Is a decent substitute for brushing after lunch — and often contains sorbitol, the thing that gives prunes their laxative effect.
68%got it wrong · 24,091 playsMedical marketplace
One back-pain patient was sent to ten different MRI centers. How many different diagnoses came back?
49.
78%got it wrong · 18,767 playsNutrition
Which healthy foods, in large quantities, can cause kidney stones?
Spinach, rhubarb, beets, Swiss chard, sweet potatoes, peanuts — and dark chocolate.
80%got it wrong · 17,261 plays
This is what health illiteracy looks like — and it's costing you.
When smart, motivated people miss facts this basic, they overuse the ER, chase supplements that don't work, and skip the benefits you already pay for. Quizzify fixes that the way these questions did — one surprising, memorable mini-lesson at a time.