Benadryl (diphenhydramine) overdose: symptoms and dangers
A Benadryl overdose can cause hallucinations, seizures and heart rhythm problems. See the signs, what to do, hidden PM products and what Benadryl contains in five countries.
Yes, you can overdose on Benadryl (diphenhydramine), and it can be serious. Too much can cause a racing heart, big pupils, dry, red skin, a high temperature, confusion and hallucinations. The FDA warns that taking more than the recommended dose can lead to heart problems, seizures, coma or death. If someone took too much, call Poison Control (1-800-222-1222 in the US) right away.
At a glance
- Diphenhydramine is the antihistamine in US and Canadian Benadryl allergy tablets, and MedlinePlus lists it in many “PM” products, such as Tylenol PM and Advil PM.
- On September 24, 2020, the FDA warned that high doses of diphenhydramine can cause serious heart problems, seizures, coma or death, after reports of teens harmed in a TikTok “Benadryl Challenge.”
- StatPearls reports that most diphenhydramine overdoses happen in children aged 6 or younger.
- The FDA says children under 2 should not get any cough and cold product that contains an antihistamine, and MedlinePlus says diphenhydramine should never be used to make a child sleepy.
- As of October 2026, “Benadryl” is a different medicine in different countries: UK Benadryl allergy products contain acrivastine or cetirizine, and the two Benadryl products on Kenvue India’s site contain no diphenhydramine.
What is Benadryl (diphenhydramine)?
Diphenhydramine is an older antihistamine. It blocks histamine, the chemical behind sneezing and itching, and it also blocks a nerve signal called acetylcholine. That second effect, called an anticholinergic effect, causes most of the danger in an overdose, according to StatPearls.
MedlinePlus says diphenhydramine treats allergy and cold symptoms and is also used for trouble sleeping in adults. It comes as tablets, chewable tablets, capsules and liquids. In the US, Kenvue’s Benadryl range also includes creams, gels, a stick and a spray for itchy skin, and its Extra Strength itch cream contains diphenhydramine.
Diphenhydramine is sold under many other names, including Nytol, Sominex, Diphenhist and store brands. You can see pictures of diphenhydramine pills to check what you have.
What are the symptoms of a Benadryl overdose?
Most symptoms come from the anticholinergic effect. Peak blood levels arrive about 2 to 3 hours after swallowing, so a person can get worse during that time. StatPearls notes that confusion caused by a drug tends to start more suddenly than confusion from an illness.
Common signs
- dry mouth and very dry eyes;
- big (enlarged) pupils and blurred vision;
- a racing heartbeat;
- dry, red skin and a high body temperature;
- trouble peeing;
- drowsiness, or the opposite: agitation, nervousness and shaking;
- confusion, unsteadiness and ringing in the ears;
- nausea and vomiting.
Sources: MedlinePlus and StatPearls.
Severe signs
- severe delirium, hallucinations or psychosis (losing touch with what is real);
- seizures;
- low blood pressure;
- dangerous heart rhythm problems, which show up as changes on a heart tracing (ECG);
- sudden muscle spasms or stiff, twisting movements (dystonic reactions);
- coma.
Our guide to the signs of an overdose compares these with the signs of other common overdoses.
Can you die from a Benadryl overdose?
Yes. MedlinePlus says few people die from an antihistamine overdose, but serious heart rhythm problems can cause death. StatPearls cites a study showing diphenhydramine overdoses made up 3.2% of US drug overdose deaths in 2016.
Survivors can also be left with lasting harm. MedlinePlus says recovery is likely if the person survives the first 24 hours. Pneumonia, muscle damage or brain damage from a lack of oxygen can still cause permanent disability.
What was the “Benadryl challenge”?
In a Drug Safety Communication on September 24, 2020, the FDA reported teenagers going to emergency rooms or dying after taking part in a “Benadryl Challenge” promoted in TikTok videos. The FDA contacted TikTok and strongly urged the company to remove the videos.
The FDA’s advice for families still applies as of October 2026:
- store diphenhydramine and all other medicines out of children’s reach and sight;
- lock up medicines to prevent accidental poisoning in children and misuse by teens;
- read the Drug Facts label and never take more than the listed dose.
Talk with teens about the FDA’s warning: too much of an allergy medicine can cause heart problems, seizures and death. If a teen seems confused or is hallucinating, treat it as an emergency.
Which sleep aids and “PM” medicines contain diphenhydramine?
Many people take diphenhydramine without knowing it. “PM” pain relievers and many sleep aids use it as the sleep ingredient. Taking two of these products together, or one with Benadryl, doubles the dose. The Advil PM label warns against using it with any other product that contains diphenhydramine, “even one used on skin.”
We checked the active ingredients of common US products on each maker’s website or label in October 2026.
| Product | Active ingredients | Watch out for |
|---|---|---|
| Benadryl Allergy Ultratabs | Diphenhydramine HCl | Same drug as the sleep aids below |
| Benadryl Allergy Plus Congestion | Diphenhydramine HCl, phenylephrine HCl | Adds a decongestant |
| Tylenol PM Extra Strength | Acetaminophen, diphenhydramine HCl | Also contains acetaminophen |
| Advil PM caplets | Ibuprofen, diphenhydramine citrate | Not for children under 12 |
| ZzzQuil Nighttime Sleep-Aid LiquiCaps | Diphenhydramine HCl | Sold as a sleep aid, not as Benadryl |
| Unisom SleepGels | Diphenhydramine HCl | Different drug from Unisom SleepTabs |
| Unisom SleepTabs | Doxylamine succinate | A different sedating antihistamine |
| Benadryl Itch Stopping Cream Extra Strength | Diphenhydramine | Counts toward the “even on skin” warning |
Sources: Kenvue (Tylenol PM, Benadryl), Haleon (Advil PM), ZzzQuil, and MedlinePlus for Unisom SleepTabs (doxylamine).
MedlinePlus lists more combination brands that contain diphenhydramine, including Aleve PM, Excedrin PM, Motrin PM, Bayer Aspirin PM and Goody’s PM. If you took too much of a PM product, the pain reliever matters too. Read our guides to acetaminophen overdose, ibuprofen overdose and aspirin overdose.
Is “Benadryl” the same medicine in every country?
No. In the Benadryl products listed below, we counted 11 different active ingredients, and none of the products we found for India or the UK contain diphenhydramine. A Benadryl box in London or Mumbai may hold a different drug from one in Chicago, and dose information you find online for US Benadryl won’t match it.
Method: in October 2026, we checked the active ingredients of Benadryl products in each country’s official medicine listing or on the maker’s own product pages.
| Country | Main Benadryl products and active ingredients | Contains diphenhydramine? | Source |
|---|---|---|---|
| US and Puerto Rico | Allergy tablets, Liqui-Gels and children’s liquid (diphenhydramine HCl); Allergy Plus Congestion (adds phenylephrine); Extra Strength itch cream (diphenhydramine) | Yes | Kenvue US product pages; FDA rules apply in Puerto Rico |
| Canada | Benadryl Allergy tablets (diphenhydramine HCl, DIN 02017849); Benadryl Allergy, Sinus & Pain Total (diphenhydramine HCl, pseudoephedrine, acetaminophen, DIN 02250993) | Yes | Health Canada Drug Product Database (non-prescription) |
| Australia | Cough liquids: Benadryl Original (diphenhydramine, ammonium chloride; Pharmacist Only); Cough Medicine for Dry Coughs (dextromethorphan, diphenhydramine); Chesty Forte (bromhexine, guaifenesin) | Some products | healthdirect, from TGA register data updated October 1, 2026 |
| India | Dry Cough Active Relief (dextromethorphan); Congestion Relief (ambroxol, guaifenesin) | No, in both products listed | Kenvue India product pages |
| United Kingdom | Benadryl Allergy Relief (acrivastine); Benadryl Allergy (cetirizine); both non-drowsy | No | NHS website |
Here is where we found each entry:
- Canada: the Health Canada Drug Product Database. You can enter the DIN on the box there, or use our NDC and DIN lookup.
- Australia: healthdirect lists Benadryl Original as a Schedule 3 Pharmacist Only Medicine. The dry cough and chesty cough liquids are Schedule 2 Pharmacy Medicines.
- India: Kenvue India’s site lists two Benadryl products. Neither one contains diphenhydramine.
- UK: the NHS lists Benadryl Allergy Relief under acrivastine and Benadryl Allergy under cetirizine. It calls both non-drowsy antihistamines.
Why this matters: if you or a child took “Benadryl” bought abroad, tell Poison Control the active ingredient on the box, not just the brand. Australian Benadryl dry cough liquid also contains dextromethorphan, and Canadian Benadryl Total contains acetaminophen, so each one carries different risks.
Why are children at higher risk?
Young children account for most diphenhydramine overdoses, according to StatPearls. The FDA says children under 2 should not be given any cough and cold product with an antihistamine or decongestant, because of risks that include convulsions, a fast heart rate and death. Makers changed their labels to say “do not use in children under 4 years of age.”
MedlinePlus adds these points:
- don’t use diphenhydramine in children aged 2 to 5 unless a doctor tells you to;
- use caution in children aged 6 to 11;
- never give children a product made for adults;
- never use diphenhydramine to make a child sleepy.
Skin products count too. In a 2019 recall notice, Health Canada said diphenhydramine cream is not recommended for children under 2, and that the drug can be absorbed through the skin in a significant amount, especially through broken skin.
Why is Benadryl riskier for older adults?
MedlinePlus says diphenhydramine generally should not be used in older adults except to manage serious allergic reactions, because it is not as safe or effective as other medicines. Its common side effects include drowsiness, dizziness and muscle weakness. Trouble peeing and blurred vision are also listed as serious side effects.
Diphenhydramine is the sleep ingredient in many “PM” pills, so an older adult may take it every night without realizing it. If you or a parent uses one for sleep, ask a pharmacist to check the label and suggest safer choices.
What should you do if someone took too much Benadryl?
- Call 911 or your emergency number now if the person is hallucinating, can’t be woken up, has a seizure, has trouble breathing or has collapsed. This is the FDA’s advice.
- Otherwise, call Poison Control. In the US and Puerto Rico, call 1-800-222-1222. The help box above lists numbers for Canada, Australia and India.
- Have the package ready. MedlinePlus says to share the person’s age, weight and condition, the product name and strength, when it was taken and how much. Call even if you don’t know all of this.
- Don’t wait for symptoms to get worse. Levels peak a few hours after swallowing, so a person who seems fine at first can get sicker.
- Follow the expert’s advice on whether the person needs to go to a hospital.
Found loose pills and not sure they are diphenhydramine? Check the imprint with our pill imprint search. A matching imprint shows what a pill should be, but it can’t prove a pill is real. Our guide on how to spot fake pills explains why.
What happens in the hospital?
Doctors check heart rate, breathing, temperature and blood pressure. MedlinePlus says tests may include blood and urine tests, a chest x-ray and an ECG to watch the heart rhythm. Treatment can include fluids through a vein, activated charcoal, medicines to treat symptoms, and help with breathing, including a breathing machine.
StatPearls says doctors may use benzodiazepine medicines to stop seizures and sodium bicarbonate for dangerous heart rhythms. With treatment, the outlook is usually good, and StatPearls says recovery is likely.
How can you prevent a Benadryl overdose?
- Read the active ingredient on every label, including sleep aids, cold medicines and itch creams.
- Use only one product with diphenhydramine at a time, including products used on skin.
- Don’t mix it with alcohol. MedlinePlus says alcohol can add to the drowsiness, and you should avoid alcohol while taking it. Our alcohol overdose guide explains why mixing sedating substances is risky.
- Never use it to make a child sleepy, and use children’s products only at the ages on the label.
- Lock up medicines if you have children or teens at home.
- Clear out old sleep aids you no longer use. See how to dispose of unused medicines.
- Check the ingredient when you travel, because “Benadryl” abroad may be a different drug.
Common questions
How much Benadryl is too much?
Any amount above the limit on the Drug Facts label is too much, and the label sets a maximum number of doses in 24 hours. The FDA warns that taking more than the recommended dose can cause serious heart problems, seizures, coma or death. The risk is higher if you take two products with diphenhydramine, add alcohol, or give an adult product to a child.
How long does a Benadryl overdose last?
Blood levels peak about 2 to 3 hours after swallowing, so symptoms can get worse during that time. MedlinePlus says recovery is likely if the person survives the first 24 hours. Complications such as pneumonia can make a hospital stay longer.
Is Unisom the same as Benadryl?
Some of it is. Unisom SleepGels contain diphenhydramine, the same drug as US Benadryl. Unisom SleepTabs contain doxylamine, a different sedating antihistamine. Check the active ingredient before you take either one with another sleep or allergy product.
Can I give my child Benadryl to help them sleep?
No. MedlinePlus says diphenhydramine should not be used to make a child sleepy. The FDA says children under 2 should not get any cough and cold product with an antihistamine. Ask your child’s doctor about sleep problems instead.
Is Benadryl in the UK, Australia or India the same as in the US?
Not always. As of October 2026, UK Benadryl allergy products contain acrivastine or cetirizine, and the two Benadryl products on Kenvue India’s site are cough syrups without diphenhydramine. In Australia, Benadryl is a cough and cold range, and only some of its liquids contain diphenhydramine. Always go by the active ingredient on the box.
