Fact or Myth: Do Mosquitoes Prefer Some Blood Types (Khoon)?
Verdict: Partly true. Blood type may make a small difference, but the evidence is mixed; the far bigger reasons mosquitoes pick you are the carbon dioxide you breathe out, your body heat and the smell of your skin.
In brief
- Verdict: Partly true. Mosquitoes do bite some people more, but “meetha khoon” and blood group are only a small, uncertain part of it.
- What is true: breath, warmth, sweat, skin bacteria, dark clothes and movement all draw mosquitoes in.
- What to do instead: use a proper repellent on skin, cover up, sleep under a net, and empty standing water around the house.
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“Tumhara khoon meetha hai”: where the belief comes from
Every family has one. At the evening chai on the roof, everyone else sits in peace while one cousin slaps his ankles every few seconds. Someone laughs and says his khoon is sweet. Later, maybe from a magazine or a forwarded message, the idea sharpens into “mosquitoes love O group.”
The observation behind it is spot on. Put five people in the same garden at dusk and mosquitoes really won’t spread themselves out evenly; one or two people will carry most of the bites night after night while the others barely notice, and anyone who has shared a roof with that unlucky cousin has seen it with their own eyes. The question is why. Not sweetness. A mosquito can’t taste your sugar level through your skin before it lands.
How a mosquito finds you, explained simply
Picture a mosquito as a tiny guided missile with three sensors, working at three distances.
- From far away (several metres): it follows the plume of carbon dioxide you breathe out. Bigger bodies and people breathing harder, such as after exercise, give off more.
- Closer in: it picks up the smell of your skin. Sweat, lactic acid and the chemicals made by the bacteria living on your skin create a personal scent, and some scents are simply more attractive to mosquitoes.
- Right next to you: it senses warmth and moisture, and it sees contrast, so dark clothes against a light background stand out.
Your skin scent is fairly stable over time, which is why the same cousin gets bitten summer after summer on the same roof while everyone else sips their chai in peace, and it seems to come partly from your genes and partly from the particular mix of bacteria that lives on your skin, not from your blood sugar or anything “sweet” in your khoon. Unlucky, not sweet.
So what about blood type?
Some lab work has hinted that type O people may be approached a bit more often, possibly because many people release chemical markers of their blood group through their skin, while other work hasn’t found a clear effect at all. Honest summary? It might play a small role, it’s nowhere near as strong as breath, heat and smell, and since nobody can change their blood group anyway, it isn’t worth a moment’s worry when the things you can change, like repellent, clothing and standing water, make a far bigger difference to how many bites you get.
Neem leaves smouldered in the courtyard, a mosquito net tied to the charpai, a bucket of water covered with a lid. The net and the covered water were excellent ideas that still hold up. Smoke, from neem or from coils, can irritate lungs, especially in children and people with asthma, so keep it outdoors and away from sleeping rooms.
Myth: eating garlic or taking vitamin B keeps mosquitoes away
This one comes back every monsoon, usually forwarded with great confidence: the idea that something you eat can change your smell enough to make mosquitoes turn away mid-flight. It hasn’t held up when tested. Garlic, bananas, vitamin B, onion: none gives reliable protection, and relying on them means skipping the things that actually work. Eat garlic because you like it, not as armour.
Also untrue: that only dirty people get bitten, or that ultrasonic buzzing gadgets and phone apps chase mosquitoes off. Clean skin still smells of you, and sound devices don’t hold up in testing.
Who genuinely gets bitten more
- Adults more than small children, because they breathe out more carbon dioxide.
- Pregnant women, who breathe out more and run slightly warmer.
- People who’ve just exercised or worked in the heat, being sweaty and breathing hard.
- People who have been drinking alcohol, according to some observations.
- Anyone in dark clothing, sitting still near dusk or near stagnant water.
What to do instead: real protection
This matters more than a joke at chai time. Aedes mosquitoes, the striped ones that spread dengue, bite in daylight, especially early morning and late afternoon, which is exactly when children are heading to school or playing outside, while Anopheles, which spread malaria, bite mostly at night. Two mosquitoes. Two shifts.
- Repellent on exposed skin: choose one with DEET, picaridin (icaridin) or IR3535, and follow the label for how often to reapply. Our repellent strength guide compares coils, creams and vaporisers.
- Sunscreen first, repellent second if you use both.
- Cover up: light-coloured, loose long sleeves and trousers in the morning and evening.
- Nets and screens: a net over beds and cots, and mesh on windows.
- No standing water: once a week, empty and scrub flower pot trays, cooler tanks, tyres and buckets. Aedes breeds in a cupful of clean water. More ideas are in mosquito control habits at home.
For babies under 2 months, use a net over the cot or pram rather than any repellent. For older children, an adult applies repellent to their own hands first and then to the child, avoiding eyes, mouth and hands that go in the mouth. More myths like this one are in Fact or Myth.
Most bites just itch. See a doctor for a bite that turns hot, spreading and painful, a blister that oozes, or swelling of the face or lips. In mosquito season, any fever with body aches, headache, pain behind the eyes or rash needs a proper check. Warning signs of severe dengue need hospital care the same day: repeated vomiting, severe tummy pain, bleeding gums or nose, black stools, extreme tiredness or restlessness, and cold, clammy skin. Don’t take aspirin or ibuprofen for a fever that could be dengue; let your doctor advise. See dengue symptoms and warning signs.
Common questions about why mosquitoes bite some people more
Which blood group do mosquitoes like most?
Type O is the one usually named, but the evidence is mixed and the effect, if real, is small. Breath, body heat and skin smell matter far more.
Why do mosquitoes bite me more than others?
Mostly because of your personal skin scent, made by sweat and skin bacteria, plus how much carbon dioxide and heat you give off. Dark clothes and sitting still near dusk add to it.
Is it true mosquitoes like sweet blood?
No. Mosquitoes choose you before they bite, using smell and breath. They can’t sense your blood sugar through your skin.
Does eating garlic stop mosquito bites?
No reliable effect has been found. Use a tested repellent, clothing and nets instead.
Do mosquitoes bite pregnant women more?
Yes, they tend to, because pregnant women breathe out more and are a little warmer. That makes repellent, nets and covered skin especially worthwhile.
What time do dengue mosquitoes bite?
Mainly in daylight, with peaks in the early morning and late afternoon. That’s why protection during the day matters, not just at night.
Which mosquito repellent is safe for children?
Products with DEET, picaridin or IR3535 are widely used for children when the label allows it for their age. Babies under 2 months should be protected with nets instead.
Do dark clothes attract mosquitoes?
Yes. Mosquitoes use sight at close range, and dark colours stand out. Light, loose clothing helps.
Do mosquito coils work, and are they safe?
They can reduce bites in a still space, but the smoke irritates lungs. Use them outdoors or in well-ventilated spots, never in a closed bedroom with a baby or someone with asthma.
Why do mosquito bites swell more on some people?
That’s your immune reaction to mosquito saliva, and it varies from person to person. Children often react more strongly. A cold compress helps the itch.