Eye drops made to clear up red eyes are safe in the eye but can be dangerous when swallowed, especially for small children. Their active ingredient works by squeezing blood vessels, and once swallowed it acts on the whole body, including the brain and heart.1JAMA. Eyedrop Risks for Kids They slow the heart, drop blood pressure, and cause deep drowsiness and slowed breathing. As little as 1 to 2 mL can seriously harm a young child. The popular belief that a few drops in a drink just cause a harmless bout of diarrhea is wrong, and people have been badly hurt acting on it.2Pharmacist’s Letter. A few drops of Visine in someone’s drink causes diarrhea Not every eye drop carries this risk. The danger is concentrated in redness-relief drops and some prescription ones, and anyone who swallows them should get poison control advice right away.
What Swallowing Eye Drops Does to the Body
Once swallowed, these ingredients act on the brain’s control of heart rate and blood pressure, so the main effects are a slow heartbeat and low blood pressure.3PubMed Central. Complete atrioventricular block due to ingestion of Visine eye drops They can also make a person very drowsy and slow their breathing.4PubMed. Visine overdose: case report of an adult with hemodynamic compromise Pupils often shrink to pinpoints, and the person may feel chest pain.5PubMed. Visine overdose: case report of an adult with hemodynamic compromise At the severe end, even small amounts can lead to seizures, a collapse of heart and circulation, and coma.6Pharmacist’s Letter. A few drops of Visine in someone’s drink causes diarrhea In one reported case, an adult’s heart rhythm was blocked so badly that the electrical signal between the heart’s chambers stopped getting through.7PubMed Central. Complete atrioventricular block due to ingestion of Visine eye drops
People often expect a “poison” to cause vomiting or a racing heart, but these drops slow the body down. The danger is quiet: sleepiness, slowed breathing, and a weakening pulse.
That quietness is why the symptoms are easy to miss. A drowsy child can look simply tired, and a slow heartbeat and low blood pressure give a parent nothing easy to see. Sleepiness after possible access to a bottle should be treated as a symptom, not a nap.
Children show these effects clearly. In 176 children who swallowed a prescription eye drop called brimonidine, about 4 in 10 became drowsy.8PubMed. Brimonidine tartrate poisoning in children: frequency, trends, and use of naloxone as an antidote Smaller numbers became unsteady, pale, irritable, or had low blood pressure, a slow heart, small pupils, or slowed breathing.9PubMed. Brimonidine tartrate poisoning in children: frequency, trends, and use of naloxone as an antidote One infant who got brimonidine drops into the nose became floppy, cold, and blue around the lips and needed a breathing tube.10PubMed Central. Respiratuvar depression after accidental nasal ingestion of brimonidine eye drops in infant
Telling ordinary sleepiness from a warning sign comes down to responsiveness. A child who is hard to rouse or goes limp again as soon as you stop is more worrying than one who wakes easily and responds normally, and so is pale, gray, or bluish skin with sleepiness. If you can’t tell which kind of sleepy it is, treat it as the worrying kind and call for help.
How a child looks at one moment can also mislead. Symptoms can build over minutes to hours, so a child who looks fine right after getting into a bottle hasn’t necessarily escaped harm. The reverse happens too: a child who seems to be recovering can drift back into deep sleep. Poison control, not how the child looks right now, decides whether watching at home is reasonable.
Which Eye Drops Are Dangerous to Swallow
In the US, over-the-counter redness-relief drops contain tetrahydrozoline, naphazoline, or brimonidine.11PubMed Central. Over-the-Counter Ocular Decongestants in the United States – Mechanisms of Action and Clinical Utility for Management of Ocular Redness Tetrahydrozoline is the ingredient in Visine and Murine Tears Plus, among others.12Pharmacist’s Letter. A few drops of Visine in someone’s drink causes diarrhea Brimonidine is also sold at a higher strength as a prescription glaucoma drop, and children have been poisoned by it.13PubMed. Brimonidine tartrate poisoning in children: frequency, trends, and use of naloxone as an antidote
Tetrahydrozoline and naphazoline belong to a drug family that also includes the decongestants oxymetazoline and xylometazoline in nasal sprays.14Federal Register. Requirements for Child-Resistant Packaging: Products Containing Imidazolines Equivalent to 0.08 Milligrams or More So a decongestant nasal spray with these ingredients carries a similar swallowing risk to redness drops.15JAMA. Eyedrop Risks for Kids Products labeled for allergies, colds, or redness can share this ingredient family, so the purpose on the front matters less than the ingredient list. A bottle of the same brand can also come in different versions, so check each bottle’s own label instead of assuming.
In an emergency, look for the “Active ingredients” box on the bottle or carton. Words ending in “-zoline” signal the risky family, and brimonidine is risky too even though it doesn’t end that way. Plain lubricating “artificial tears” usually list ingredients like carboxymethylcellulose instead. Keep the bottle so you can read the ingredient and strength to poison control.
These drugs hit hard when swallowed because they work the same way as clonidine, a blood pressure pill. In the eye only a tiny amount reaches the blood, but swallowing delivers the whole dose. A child’s small body weight means a few milliliters is a large one.
How Much Is Dangerous for a Child
Swallowing as little as 1 to 2 mL of these drops or sprays can cause serious harm in young children.16JAMA. Eyedrop Risks for Kids One milliliter is about a fifth of a teaspoon, and a typical small eye drop bottle holds many times that. A child chewing or sucking on a bottle tip can easily get that much, and you usually can’t tell how much is gone, so assume the worst. Children are hit harder than adults because dose depends on body size, and they tend to swallow the product in one go rather than getting it as drops in the eye. Any amount a child may have swallowed is worth a call to poison control.
The US requires child-resistant caps on any product with 0.08 mg or more of these ingredients in one package, to protect children under 5.17Federal Register. Requirements for Child-Resistant Packaging: Products Containing Imidazolines Equivalent to 0.08 Milligrams or More Those caps slow children down but are not childproof. A cap left loose, or a bottle carried loose in a purse, loses that protection, and older products or travel sizes may be easier to open.
What to Do Right Away
Call Poison Control at 1-800-222-1222 in the US right away, even if the person seems fine. Call 911 instead if the person is hard to wake, breathing slowly, has a seizure, or turns pale or blue. Have the bottle in hand so you can read the ingredient and estimate how much is missing. Don’t try to make the person vomit unless poison control tells you to.
While you reach help, take the bottle away and, if the child has any in the mouth, wipe it out gently with a cloth. Have an awake child sit up rather than lie flat, and stay with them. If the child is limp, unresponsive, or not breathing normally, call 911 first and follow the dispatcher’s instructions.
The poison control call is free and staffed around the clock. They ask the person’s age and weight, the product, and how much may be gone. They also ask when it happened and whether symptoms have started. Then they tell you whether to watch at home or go to the emergency room.
If you’re told to watch at home, keep the person awake enough to check that they respond normally. Watch breathing, skin color, and how alert they are. Go in at once if sleepiness deepens or breathing slows.
How Hospitals Treat Eye Drop Poisoning
Doctors treat swallowed redness drops the same way they treat an overdose of clonidine, a blood pressure drug with matching effects.18PubMed Central. Ingestion of Fluids of the Ocular Surface Containing Eye Drops of Imidazole Derivatives—Alpha Adrenergic Receptor Agonists as Paragons Staff usually begin with the basics: how alert the person is, heart rate, blood pressure, breathing, and oxygen level. They check temperature and pulse too, and may run a heart tracing, blood and urine tests, and a chest x-ray.19MedlinePlus. Tetrahydrozoline poisoning Tell them the product, ingredient, and time, and hand over the bottle if you brought it, so the team can match care to the exact ingredient and strength.
Treatment can include activated charcoal, IV fluids, medicines for symptoms, and oxygen or a breathing machine if breathing is too slow.20MedlinePlus. Tetrahydrozoline poisoning Naloxone, the opioid-reversal medicine, has been studied as a possible antidote in children poisoned by brimonidine.21PubMed. Brimonidine tartrate poisoning in children: frequency, trends, and use of naloxone as an antidote
For families, that usually means a child is watched for several hours even if they look well. Heart monitor stickers and a finger oxygen clip are routine. Most care is supportive while the body clears the drug, and a breathing tube is reserved for severe cases.
The Eye Drops in a Drink Prank Is a Myth
The idea that a few drops in a drink cause harmless diarrhea was popularized by a scene in the 2005 movie Wedding Crashers.22WIRED. Just an (Eye) Drop of Poison Swallowed eye drops don’t cause a harmless bout of diarrhea; they cause the slowing effects above, and people have been seriously harmed by this “prank.”23Pharmacist’s Letter. A few drops of Visine in someone’s drink causes diarrhea One woman told police she got the idea to spike her fiance’s soda from that movie.24ABC News. North Carolina woman tried to spike fiance’s soda with eye drops, police say
The dose in a drink is unpredictable. The person drinking has no way to know how much they got, and the person spiking it can’t know how it will affect that body. Alcohol is itself a sedative, so combined with these drops it can deepen drowsiness and slow breathing further. And spiking a drink can lead to criminal charges.
It has also been used as a weapon. Among 18 reported cases of non-medical tetrahydrozoline use, cases included sexual assault, attempted murder, and suicide attempts, alongside accidental swallowing.25PubMed Central. More than meets the eye: a scoping review on the non-medical uses of THZ eye drops In one case a mother deliberately gave her child the drops, and the child arrived lethargic with a slow heart and pinpoint pupils.26PubMed Central. More than meets the eye: a scoping review on the non-medical uses of THZ eye drops
The ingredient can still be found in urine about 20 hours after it was given.27PubMed. Drug-facilitated sexual assault using tetrahydrozoline So if you suspect your drink was spiked, ask the hospital to test your urine and tell them eye drops may be involved.
If Your Dog or Cat Gets Into Eye Drops
The same decongestant ingredients in eye drops and nasal sprays are toxic to dogs that swallow them.28Pet Poison Helpline. Dangers of Dogs Ingesting Eye Drops Some of these products also contain xylitol, a sweetener that is dangerous to dogs.29Mallard Creek Animal Hospital. Nasal Spray and Eye Drop Poisoning in Pets A pet chewing a bottle is a medical emergency, and even small amounts can be dangerous.30Mallard Creek Animal Hospital. Nasal Spray and Eye Drop Poisoning in Pets
Dogs poisoned this way may become very sleepy, wobbly, or weak, with a slow heartbeat and low body temperature. Drooling, vomiting, or collapse can follow, so any sudden change after chewing a bottle is a warning. Cats are smaller and can be affected by smaller amounts, so treat them just as seriously.
Take the bottle away, gather the packaging, and call your vet or the Pet Poison Helpline right away. Don’t induce vomiting unless a vet tells you to, since it can be unsafe in a drowsy animal. Be ready to give the pet’s weight, the product name, and how much may be missing.
Keeping Eye Drops Away From Kids
Treat redness drops and decongestant sprays like medicine, not like a harmless toiletry. Store them up high in a closed cabinet, and close the child-resistant cap fully after each use.31Federal Register. Requirements for Child-Resistant Packaging: Products Containing Imidazolines Equivalent to 0.08 Milligrams or More Children climb and open things, so a high, latched cabinet is more reliable than a low one.
Don’t leave a bottle on the counter while you put drops in a child’s eyes or your own, since a curious toddler can grab it in seconds. Keep it in your hand or put it away right after use. If you give drops to a pet, be careful that they don’t lick or chew the bottle.32Pet Poison Helpline. Eye Drop Poisoning in Dogs
Drops get forgotten in purses, diaper bags, and coat pockets, on bedside tables, and in car cup holders. Guests’ and grandparents’ bags during visits are easy to overlook. Save the poison control number in your phone now, so it’s there when you need it.