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People are generally aware that a musty and damp smell may indicate mold, which is never a good thing to be around. However, there are other odors that we may not know could put us in grave danger.
Recently, a few people on Reddit provided insight into what these smells are. A lot of these are not what you would expect, especially since they resemble the scent of something completely harmless, like a fruit.
Feel free to research these for validation, but the responses on this list are worth noting nonetheless.
This post may include affiliate links.
#1
The smell of Axe Body Spray in a room with no ventilation. It doesn't mean danger is coming; it means danger is already here, it’s 19 years old, it hasn't done laundry in three weeks, and it wants to explain crypto to you.
LakotaWolf (she/her) 7 hours ago
PLEASE tell me that isn't an actual Axe scent. Good lort. I use Axe deodorant because it's stronger than lady deodorant, but I use a lovely "dark chocolate" scent. I cannot fathom why one would want to mix shoes with cookies. I have questions that I don't know if I want the answers to. Are the sneakers new? Old? Are they a teenager's sneakers? What type of cookies? Does it smell like sneakers AND cookies, or does it smell like sneakers that were stuffed full of cookies a week ago and your teen child left them in the back of their closet?
RELATED:
#2
If you’re out in the woods and you randomly smell bananas; back away as carefully and quietly as you can… angry bees release a “fight” pheromone that smells like bananas to us.
Also not a good idea to eat bananas near a swarm for the same reason.
WindySwede 2 hours ago
never smelled that in bee hives here, even if they are upset with the last harvest of the season.
#3
Fishy smell in your house with no fish. That usually means an electrical fire is starting like wires melting/burning. Turn off the main breaker and call an electrician immediately.
SignNotInUse:
Melting wiring doesn't always smell obviously fishy. Sometimes it smells more like nail varnish remover with a hint of hot metal. I ignored a mystery chemical smell caused by a light switch slowly melting itself because it didn't smell obviously fishy.
Swayerst:
One day my hallway smelled unmistakably of fish and I thought I was losing it. Best theory I had was that my kiddo had something weird in her pockets in the dryer. I finally googled "Why does my hallway smell like fish" as a hail mary... Turns out the dryer plug was halfway melted.
Norm Gilmore 6 hours ago (edited)
Have been to many homes where people are apologetic for calling me in because of the 'fish' smell but are very happy to find out it's not their imagination when I show them the baked lamp holder. Usually from not following manufacturers instructions. Don't put a 100w incandescent lamp into one that's only rated at 40.. (Not as big a problem now though since LEDs have become cheaper/available)
#4
Sour apple juice. If your urine smells like this, and you are not purposefully dieting, it could be diabetes. Have your blood sugar checked immediately. Most pharmacies can help.
PlsKpopMe:
Hey so thank you for this... I just got up to pee in the middle of the night and it smelled so bad like sour apple juice It woke my son up for him to tell me "mom your pee stinks so bad it woke me out of my sleep from my room"... I will make an appt tomorrow.
#5
The smell of sulfur inside your home.
Indication of a gas leak.
Dense_Tonight9891:
That rotten egg / sulfur smell. Once you know it’s the added odor for gas leaks, you never forget it, and it’s one of those things you should immediately take seriously.
RosemarieAllan:
Rotten eggs, sulfur, or sometimes a skunk-like odor usually mean there's a gas leak.
#6
Ketones on someone's breath.
If they aren't doing a Keto diet and intentionally triggering this, it's a sign of diabetic ketoacidosis and could be life-threatening.
I recognized this on my husband and told him that he needed to see a doctor; he was diagnosed with diabetes a week later.
Nassi_:
My wife noticed it on me in October of 2024. I was actively going into diabetic shock. My A1C was 19 and my blood sugar was in the 700’s. It was then that I was diagnosed with being a type 2 diabetic. I spent a week in the hospital. She said I smelled of syrup and slightly of mildew. I was hours from death, my wife literally saved my life that day.
#7
If you are ever hiking near a river or a canyon after a rain storm and suddenly is smells really strongly like trees and earth get to high ground immediately. Flash flood is coming.
#8
I experience a weird smell like I’ve just sucked a bunch of pool water up my nose before fainting spells and other medical episodes. Hard to describe but kind of chlorine-y or metallic or just… sterile? with a strange sensation in the sinuses. So if that smell hits you, lay down!
niccheersk:
I used to smell this all of the time to the point my family thought I was crazy for searching for spilled cleaner everywhere. It was so strong it made me nauseous. Turns out, my spinal fluid was leaking out of my skull and into my nose. I had a constant running nose that I kept being told was just allergies and headaches so bad I could barely function, and they kept telling me it was just migraines.
#9
Breath that smells like nail polish remover. I had a student once who walked up to me and told me she didn’t feel well. I had noticed she kept putting her head down on her desk. When she started talking to me her breath smelled just like nail polish remover. Called mom who took her right to the dr and they tested her sugar. Juvenile diabetes. She landed in the hospital for several days.
#10
Bitter almond smell can mean cyanide is present. Not everyone can smell it, however. Uncommon and unlikely to encounter, but thought I’d mention anyway.
#11
Maple syrup. Two different jobs trained me for that smell. The first was a corrugated steel pipe factory. If you smelled maple syrup, that meant that oil was burning on the weld and you were going to have a bad time. The second being a truck driver. If you smell maple syrup, that means your oil is burning or leaking somewhere and also, you're going to have a bad time.
#12
Ozone.
I smelled it in my backyard once, then heard a hiss and then KABOOOOOM!!!! Lightning struck an apple tree that was about ten meters from me.
The whole event took fractions of a second but my brain picked out each step like that.
In fact, I think the hiss came first, then the smell of burning air and then the blinding white light and then the soul-splitting cracking sound.
Lightning sounds totally different up close like that. It was terrifying jfc.
Jharic_:
Nothing smells like ozone. It's so metallic. You can taste it and it changes the smell of everything around you. Had the same thing happen when a lightning bolt struck a tenants car 15 feet from my studio window. Our window was open because it was summer and the cool rain and breezy wind made us feel nicer. Just like you said CRACKLE BAM! metal
#13
If you smell cilantro (coriander) when you are near the bed in your hotel room.... that indicates bed bugs.
west211:
I've always thought that cilantro smells like dirty sheets, now I know why! How can people eat that!?
Laura Gillette 7 hours ago
The smell of cilantro makes me want to gag, so this would be easy for me to detect.
#14
Ammonia. Rotting meat releases ammonia which gives it that distinctive smell, warning us not to eat it. But in my line of work (warehouse/food distribution) the refrigerator systems use anhydrous ammonia. If you smell it, you pull the fire alarm and get everyone out. Even a little direct exposure to those vapors can blind you, or [end] you.
Lil be lil 4 hours ago (edited)
I don't really understand this. If I open a bottle of ammonia and smell it I should run? And how does it blind or k**l you.?
#15
Rotting potatoes.
It is the most noxious smell you'll ever come across and if there are enough decomposing potatoes in a confined space it can be fatal.
Glittering-Brick-942:
I worked at a farm stand and getting to the middle of a box and finding 4 liquid potatoes is one of the worst things. Id rather change diapers with my eyelids than have to sort potatoes again,
Midoribird Aoi 5 hours ago
Ogh. Oh God. Am a cashier at a grocery store. Trust me. I always, ALWAYS know when your bag of potatoes is bad!
#16
Toast or cigarette smoke when none is present (called phantosmia, or phantom smells) can signal something minor, like a sinus/respiratory infection or major, like a epilepsy/neurological event.
LakotaWolf (she/her) 6 hours ago
I smell phantom smells right before a bad migraine hits me. Sometimes it smells like rotting oranges, sometimes it smells like acetone, sometimes it smells like rot. I used to ask my ex "Do you smell that?" and wander around the house trying to find the source of the smell. Turns out it's all in my brain! (I also get the aura/phantom lights when I get bad migraines too. Really bad migraines are almost trippy, and not in a good way.)
#17
If your phone smells like super glue, that's a lithium leak, get the battery replaced or get a new phone ASAP.
#18
If you’re outside and smell cucumber all of the sudden, you may be near a venomous Copperhead snake. They let off a musk that smells similar to cucumber when they’re threatened.
#19
If you smell chlorine, particularly indoors, and you are no where near a pool, someone accidentally mixed household cleaners (commonly bleach and drain-o) and they just created chlorine gas. Get outside and call the fire department.
#20
If you’re on your phone, laptop or similar device powered by a Li-ion battery and suddenly get a smell that’s fruity or like nail polish, congratulations you likely have a swollen battery (or, as the internet likes to call them, spicy pillows) on your hands.
Stop using the device and replace the battery immediately, safely disposing of the old one while NEVER applying pressure to it.
#21
If someone's breath smells like they're decaying from the inside out, tell them to go get checked. I don't mean bad breath, I mean, like literal rotting meat mixed with eggs, almonds, and something sweet. I first smelled it on my dad's breath. My brain instantly knew what it was, but I didn’t believe it. Turns out he had cancer and was too far gone. He passed a month later.
I have since smelled that same smell on a few people with cancer since, and it gives me this horrible feeling in the pit of my stomach.
#22
A combination of a horse stall/petting zoo and coffee grounds.
That’s male bear urine.
#23
If it smells like cut grass and nobody has been cutting grass nearby, it's phosgene gas.
If a pill smells like almonds, it's cyanide.
EDIT: Just wanted to take advantage of the high upvotes to put this out there: Phosgene gas can be released when a welding arc makes contact with certain cleaning agents, notably brake cleaners. People have [[passed] because of this. Anyone who welds should make sure to know what cleaning agents they are using and what happens when those cleaning agents make contact with a welding arc. As others have pointed out, by the time you smell phosgene gas, it's probably already too late.
#24
Rotting fish if you’re out hiking.
Bears, but grizzly bears in particular, smell *very* strongly of rotting fish, especially in the fall when they’re eating nothing BUT fish.
Bears also tend to be more aggressive during this time, because it’s both mating season and heavy feeding time. They get a sudden boost of eating energy to eat as much fatty foods as they can lay their paws on before hibernation, and they get kinda cranky.
#25
Whenever my car smells weirdly sweet like syrup while I’m driving, I’m pulling over because that coolant leak can turn bad fast.
tumblrout:
Aircon condenser leak smells like durian.
#26
C-Diff infection.
dum_spir0_sper0:
I’ve spent years working in an ER and am very familiar with the smell, it truly is quite hard to describe but I’ll try…
It’s a sharp, fetid, organic smell. It definitely smells like feces, but sour ‘unhealthy’ feces with a bit of that sickly sweet infection smell around the edges. I’ve gotten used to the smell of blood, viscera, UTIs, and almost anything else the body can produce… but this is one of those smells that punches you right in the face. Like digested blood. That’s another one you’ll never get used to.
#27
The smell of blood. Unmistakable, and if you can smell it that means that there is a lot of blood around, as you won't smell just a drop.
atowncalledfinger:
Smells like old pennies.
#29
Not sure if the brand is known around the globe, but if you smell Maggi (liquid seasoning for soups) in the forest, you should watch out for wild boars (they smell like it, especially in groups or when marking territory).
#30
Drakkar Noir, you’re gonna want to keep a close eye on your drink.
LakotaWolf (she/her) 6 hours ago
I think OP is trying to be hilariously witty by saying that if you smell this scent, which is a men's cologne, watch your drink at a bar because you're about to get roofied by the man wearing it.
#31
If you’re outdoors and smell a strong cooking potatoes or rotten potatoes smell - and no one is cooking potatoes - it’s a sign of a cobra nest nearby.
#32
Kidney failure in people has a distinct smell, possibly when combined with diabetes. Sickly sweet, but also stale urine.
#33
Bedbugs smell bitter/acrid. If you walk into a hotel room, someone’s house, or near the back row of a movie theater and the air is weirdly acrid, don’t sit down! Just head on out and save yourself lol. Source: I am an entomologist and one of my college professors kept a little bedbug colony for students and local pest control professionals to sniff, so we could commit the smell to memory.
#34
E. coli bacteria.
Had a friend who worked in a research lab with E. Coli bacteria in college. A group of us went out to eat one day to try an all you can eat sushi place, and as soon as we walked in the door our friend said the place a strong E. Coli smell to it. While waiting for a table he convinced us to bail. We looked it up later and some people had left reviews online saying they got sick there.
I guess he was just hyper sensitive to the smell from being in the lab. So, my answer is E. Coli.
ElevatorEquivalent41:
As someone who also works with e. coli in a lab: it smells like straight up colon mixed with wet dog. it’s pretty gross.
#35
I've been on fire before, it's a weird smell, quite unique too.
LakotaWolf (she/her) 6 hours ago
I had a biopsy done on my right shoulder when I was a teenager (turned out to be a precancerous mole, yay.) The dermatologist cauterized the biopsy spot. He'd only used a local anesthesia, so I was awake. Burning human flesh and skin really DOES smell like pork. Specifically, it smelled like Mexican pork carnitas and chicharrónes (a snack made from fried pig skin.) I haven't been able to eat either one since, which is awkward since my adoptive family is Mexican XD
#36
Anytime I suddenly feel dizzy or nauseous around a heater or generator and smell nothing at all, I’m thinking carbon monoxide and getting outside immediately to check what’s wrong.
WindySwede 2 hours ago
Can you feel that so fast, or is this psychosomatic? CO can be lethal, so don't get me wrong. But what are the symptoms and is that so quick? Also get an CO-alarm!
#37
Decomposing human tissue. I was a paramedic for a decade and a half and have stumbled upon several bodies over the years that had been down for a while. It has a very distinct smell, especially as time goes on. I cant describe it but i can still taste and smell it if i think about it.
#38
All my vet techs and shelter workers know, you can walk into a quarantine room and immediately know which animal has giardia before the samples even get to the lab 🤢.
TheOGPotatoPredator:
I haven’t been a vet tech for almost 25 years and I still can remember what it smelled like when we had a poor doggo with parvo.
VetTech_FarmMom:
Parvo..if I could let people smell parvo I swear they’d get their damn shots..the metallic/iron/intestine lining smell is never forgotten
LakotaWolf (she/her) 6 hours ago
My dog Stilgar had distemper when he was a puppy and survived; it's on par with parvo with its mortality rate in puppies (80%-90% fatal.) I can't remember him having a particular smell to him when he was sick XD I guess distemper doesn't have a smell to it like parvo does.
#39
I’ll share one from personal experience. I have Crohn’s disease and one of the first symptoms I get of a flare stating was that my gas smelled like absolute [demise]. It seemed random at first, but over time it’s pretty clear that it’s the smell of inflammation causing serious damage and thus an incoming massive increase in symptoms.
…this is not particularly relevant to most people though. Still, it might be worth considering if your farts randomly start smelling really bad that it’s almost definitely either a major change in your gut microbiome or damage being done to your intestines so you should potentially get it checked out, at least if it isn’t a one time thing.
#40
Ammonia. A warehouse across from where I worked purged their massive tanks "accidentally". We all almost [passed]. Good times.
#41
I live in Alaska. In deep brush, you will smell the bear before you see it, if you're lucky. And even if you've never even been in the woods before, you will instinctively know what that smell is. We're hard-wired to respond to that smell.
Smells foul. What I'm talking about is usually in the spring, right after they come out of the den. Urine and feces mixed with really bad breath and rotten meat are as close to what it is as I can get. They lose most of that smell after shedding their winter coat.
But even a bear in the fall will have a distinct odor. You'll just know, trust me.
#42
A STRONG smell of chlorine or a sharp, chemical odor near an ice rink, not caused by swimming pool chemicals, but rather by byproducts from the Zamboni or, more seriously, an AMMONIA LEAK from the refrigeration system.
I was at a golf driving range, later in the evening, downhill of an ice rink, you could see a white cloud rolling down the hill like fog just feel the oxygen being sucked out off the air. FIND HIGHER GROUND IMMEDIATELY as there is an extremely high likelihood of asphyxiation risk. There was a severe leak in the equipment and fire fighters said it’s a good thing we acted quickly.
#43
Skunk. Emotionally draining and ever present. I’m biased because I’m currently dealing with skunks mating and spraying in the basement without any help from the landlord, of course. Yes, I appreciate the irony of my username right now.
Bored Jellyfish 7 hours ago (edited)
Just my weird perception, but the smell of skunk has a bit of a sesame seed oil tinge to it to me.
#44
This one is very niche and I hope nobody ever has to use it but I learned it from the Marines. If you're ever in a combat zone and smell cinnamon, it means someone nearby is making IEDs. They cover it with cinnamon to throw off dogs.
#45
Gas. If you smell it, that’s not a “maybe later” situation.
#46
Anytime the basement smells heavy and musty all the time, I’m thinking mold and long-term health issues.
#47
Any abrupt change in the prevailing scents may indicate that something new is burning. Such as your pants. Ask me how I know.
#50
The smell of lovage in the woods > wild boars are nearby and they can be very angry.
LakotaWolf (she/her) 6 hours ago
Lovage is an herb. Someone on Reddit described it as "it's related to celery and smells pretty similar (especially to celery leaf), but a little more licoricey or anise-y"
#51
Hot brakes...either you or someone driving near you is in trouble.
#52
I work on a petrochemical plant. Sweet, rotten fruit, leak at Solvents plant. Rotten eggs, leak at Sulphur plant. Bitter ozone, leak at Oxygen plant. Sweet plasticy smell, leak at Phenosolvents plant. It sounds like the plant is falling apart from this explanation, but I've lived in the town adjacent all my life and worked inside the plant for well over a decade.
#53
My husband's sweat gets a weird smell right before he has a seizure. So I recognize that as danger. Apparently I'm the only one who can smell it. I guess the dogs too.
#54
Love Spell.
hexensabbat:
This is my toxic sister's all time favorite scent, so yes I agree.
#56
Certain after-shaves worn by skeevy older guys in red hats. And also that cloying blend of “lilac and Ugh” by their wives. The smell of natural animal decomposition is more pleasant than the aforementioned decay of these soulless ghouls.
#57
That sharp electrical burning smell - like hot plastic or fried wiring. The second you catch that, something is not okay.
What do you think ?
Bored Jellyfish 6 hours ago
Palmetto bugs (aka “Florida woods cockroach” which look like armored cockroaches) in Florida put out a scent when threatened (or when you’re actively k*****g them) that kind of smelled like Play-doh to me.
Bored Jellyfish 6 hours ago
Palmetto bugs (aka “Florida woods cockroach” which look like armored cockroaches) in Florida put out a scent when threatened (or when you’re actively k*****g them) that kind of smelled like Play-doh to me.
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