Benadryl and Alcohol: Why You Should Not Mix Them

Do not drink alcohol when you take Benadryl (diphenhydramine). The over-the-counter Drug Facts label says so directly: when using this product, avoid alcoholic drinks; marked drowsiness may occur; alcohol, sedatives, and tranquilizers may increase drowsiness; and be careful when driving a motor vehicle or operating machinery. Both alcohol and diphenhydramine slow the central nervous system, so together they add up, and the impairment can be greater than you feel.

The strongest evidence for how much greater comes from a driving-simulator study. A single 50 mg dose of diphenhydramine caused worse driving performance than the impairment from a blood alcohol level of 0.10, which is above the legal limit in the United States. The authors concluded diphenhydramine may affect complex tasks like driving even more than alcohol does. Add alcohol on top, and the effect compounds.

This guide explains what Benadryl is, what the label says, what studies show about impairment, why “I don’t feel sleepy” is not a safe test, which products contain diphenhydramine (many sleep aids do), risks for older adults and children, what the FDA warned about high doses, alternatives, and what to do if you have already mixed them.

This is general information based on FDA labeling, FDA safety communications, and published research, not medical advice. For a severe allergic reaction with trouble breathing, use epinephrine if prescribed and call 911.

Table of Contents

Benadryl and alcohol at a glance

What the Drug Facts label says	Avoid alcoholic drinks; alcohol, sedatives, and tranquilizers may increase drowsiness; be careful driving or operating machinery
Why	Both depress the central nervous system; effects add together
Key study	A single 50 mg dose impaired simulated driving more than a blood alcohol level of 0.10
Important warning	Impairment can occur even without feeling sleepy
Extra risks	Older adults (confusion, falls), children (excitability), and high doses (heart problems, seizures)
Safest approach	No alcohol with Benadryl or any diphenhydramine product; do not drive

What Benadryl is

Benadryl is the best-known brand of diphenhydramine, a first-generation antihistamine. It blocks histamine, the chemical behind sneezing, itching, hives, and watery eyes. It is used for allergy symptoms, hives, and insect bites, and in some products for cold symptoms, motion sickness, and sleep.

“First-generation” matters. These older antihistamines cross easily into the brain, where they cause drowsiness. They also block another chemical messenger (acetylcholine), which is why they can cause dry mouth, blurred vision, constipation, trouble urinating, and confusion, especially in older adults. Newer antihistamines such as loratadine and fexofenadine are designed to be less sedating. See our comparison of Allegra vs Claritin.

What the label says

The Benadryl Drug Facts, and the label for generic diphenhydramine products, include this in the “When using this product” section:

Marked drowsiness may occur
Avoid alcoholic drinks
Alcohol, sedatives, and tranquilizers may increase drowsiness
Be careful when driving a motor vehicle or operating machinery
Excitability may occur, especially in children

These instructions appear on the box because the combination is a well-recognized safety issue, not because it is rare or theoretical.

How the two interact

Alcohol depresses the central nervous system: it slows reaction time, impairs coordination and judgment, and causes sleepiness. Diphenhydramine does the same through a different mechanism. A safety fact sheet on diphenhydramine put together for the National Transportation Safety Board states that the effects of diphenhydramine are increased by the presence of alcohol, MAOIs, diazepam, hypnotics, sedatives, tranquilizers, and other CNS depressants, and that alcohol enhances effects such as drowsiness, sedation, and decreased motor skills.

The effects are additive or worse. Taking them together can cause:

Heavy drowsiness or sudden sleepiness
Slowed reactions and poor coordination
Dizziness and unsteadiness, raising the risk of falls
Confusion or memory gaps
Slowed breathing at higher doses
A false sense of being fine, followed by impairment that shows up when you are driving or doing something risky

“I don’t feel sleepy, so I’m fine”: a dangerous assumption

The same fact sheet notes that diphenhydramine causes significant adverse effects on vigilance, divided attention, working memory, and psychomotor performance, and that impairment has been shown to occur even in the absence of self-reported sleepiness or sedation. In other words, you can be impaired without feeling impaired.

The clearest illustration is the driving study. Researchers at the University of Iowa’s driving simulator compared the effects of a single 50 mg oral dose of diphenhydramine with those corresponding to a blood alcohol concentration of 0.10 g/100 mL. They found that diphenhydramine caused significantly less coherence (the ability to maintain a constant distance behind another car) and worse lane keeping, with steering instability and crossing the center line, compared with alcohol. Overall driving performance was poorest after diphenhydramine, and participants were also the most drowsy after taking it. The authors concluded that diphenhydramine clearly impairs driving performance and may have an even greater impact than alcohol on the complex task of operating a motor vehicle.

Now consider what that means when you add alcohol to diphenhydramine. Each impairs driving on its own. Together, the effects add up. This is why the safe advice is never to drive after taking Benadryl, and never to drink alongside it.

Hidden diphenhydramine: products to watch

Many people take diphenhydramine without thinking of it as “Benadryl.” It is an active ingredient in a long list of products, including:

Sleep aids such as ZzzQuil and many store-brand “nighttime sleep aid” products
“PM” pain relievers such as Tylenol PM and Advil PM, which pair diphenhydramine with a pain reliever
Allergy and cold products that list diphenhydramine HCl in the Drug Facts
Some cough and cold formulas and motion sickness products
Anti-itch creams and gels, which are applied to the skin and are absorbed much less, though large amounts can still enter the blood

Always check the “Active ingredients” section of the Drug Facts. If it says diphenhydramine, the alcohol advice applies. If your product also contains acetaminophen, alcohol adds separate liver risks, so limit or avoid alcohol and never exceed the labeled maximum dose of acetaminophen.

Using Benadryl as a sleep aid with alcohol

A common and risky pattern is taking diphenhydramine to fall asleep, sometimes after drinking. Some people think of it as a way to sleep off a night out. This is a poor idea for several reasons:

Alcohol fragments sleep and can worsen sleep quality, and diphenhydramine does not fix that.
Both cause next-day grogginess, and the hangover-like effect can make driving in the morning unsafe.
Tolerance builds quickly to diphenhydramine’s sleep effect, which means it works less well after a few nights, and heavier use follows.
The combination can slow breathing in some people, especially with higher doses or other sedatives.
The underlying problem stays. If you cannot sleep, the cause matters, and better options exist, such as consistent routines, treating anxiety, and cognitive behavioral therapy for insomnia.

Our sleep debt calculator can help you see how much sleep you may be missing, and our guide to mindfulness techniques includes a body-scan practice that many people use at bedtime.

High doses: the FDA warning

In September 2020, the FDA issued a Drug Safety Communication warning that taking higher than recommended doses of the common over-the-counter allergy medicine Benadryl (diphenhydramine) can lead to serious heart problems, seizures, coma, or even death. The warning followed news reports of teenagers ending up in emergency rooms or dying after participating in the “Benadryl Challenge,” which was encouraged in videos on social media.

The lesson is simple: more is not safer. The labeled dose is the dose. Taking extra to sleep better, to counteract a reaction, or because “it’s just an allergy pill” carries real danger, and adding alcohol raises that danger. If someone has taken too much diphenhydramine, call Poison Control (1-800-222-1222 in the United States) or emergency services immediately.

Who should be most careful

Avoid combining alcohol and diphenhydramine, and be especially cautious with diphenhydramine at all, if you:

Are an older adult. First-generation antihistamines can cause confusion, dizziness, falls, urinary retention, and worsened memory in older people. Geriatric prescribing guidelines generally advise avoiding them in this age group. Alcohol adds to fall risk.
Are giving it to a child. Children may become excited or agitated instead of drowsy. Never give it to make a child sleepy, and never give a child alcohol or products that contain it.
Have glaucoma, an enlarged prostate, trouble urinating, or asthma. The Drug Facts label advises asking a doctor before use in these conditions.
Have liver disease or drink heavily. These can raise risk.
Take other sedating medicines, including sleeping pills, anti-anxiety drugs, opioids, muscle relaxants, and many antidepressants or antipsychotics.
Are pregnant or breastfeeding. Ask your doctor.
Drive, operate machinery, or care for others during the hours you would be affected.

How long to wait

Benadryl’s typical adult label dosing interval is every 4 to 6 hours, which reflects how long its effects generally last. But impairment can outlast how you feel, and the drug can stay in the body longer, especially in older adults, people with liver disease, and after repeated doses. There is no official waiting time on the label, because the instruction is to avoid alcohol while using the product.

A practical rule: do not drink on the same day you take diphenhydramine, and do not take it on a day when you have been drinking. If you take it for several days in a row, avoid alcohol for that whole period and until its effects have clearly worn off. Ask your pharmacist about your situation.

If you have already mixed them

Do not drive, cycle, or operate machinery. Arrange another way home.
Stay somewhere safe, ideally with someone who can check on you.
Do not take more Benadryl or any other sedating product.
Avoid more alcohol.
Sleep on your side if you are very drowsy, and do not lie flat on your back.
Call Poison Control (1-800-222-1222) or a pharmacist if you are unsure.
Get emergency care for trouble breathing, slow or shallow breathing, a very fast or irregular heartbeat, seizures, severe confusion, hallucinations, fainting, or if the person cannot be woken.

When the allergy is the real problem

Benadryl is often taken for allergic reactions, and here the priorities are different. Benadryl is not a substitute for epinephrine in a severe reaction. For anaphylaxis, with signs such as trouble breathing, throat swelling, widespread hives with dizziness or vomiting, epinephrine is the first-line treatment and 911 should be called. Antihistamines may help with itching and hives afterward, but they do not treat airway swelling or low blood pressure. See our guides to EpiPen vs Benadryl and epinephrine auto-injectors.

If you get hives, flushing, or a stuffy nose whenever you drink, do not just treat it with an antihistamine. Persistent reactions to alcohol can have many causes, such as sensitivity to ingredients in drinks (sulfites or histamine-related compounds), differences in how your body breaks alcohol down, or a true allergy. A clinician can help sort it out, and masking symptoms with medicine is not a safe long-term plan.

Less sedating alternatives

If your goal is allergy relief without drowsiness, ask your pharmacist or doctor about alternatives:

Second-generation antihistamines such as loratadine, fexofenadine, and cetirizine are less likely to make you drowsy. Cetirizine can still cause sleepiness in some people, and all antihistamines should be read on their labels. See our comparison of Allegra vs Claritin and our guide to Allegra Hives vs Allegra.
Steroid nasal sprays for nasal symptoms. See Flonase vs Nasacort and Nasonex vs Flonase.
Antihistamine eye drops for itchy eyes. See Pataday vs Zaditor.
Avoiding triggers and treating the cause where possible.

Even with less sedating options, read the label, since some carry alcohol cautions of their own. For sleep problems, talk to a doctor about safer approaches than an antihistamine.

Questions to ask your pharmacist or doctor

Do any of my medicines or supplements contain diphenhydramine?
Is there a less sedating option for my allergy?
How long should I wait to drink after taking diphenhydramine?
Is diphenhydramine safe for me, given my age and other medicines?
What should I take if I need help sleeping?
What symptoms should make me seek emergency care?

Frequently asked questions

Can you drink alcohol after taking Benadryl?

The Drug Facts label says to avoid alcoholic drinks when using Benadryl, because alcohol may increase drowsiness. Combining them can impair your coordination, judgment, and reaction time more than either alone.

How long after Benadryl can I drink alcohol?

There is no set time on the label, and effects can last longer than you feel them, especially in older adults or with liver disease. The safest approach is not to drink on a day you take diphenhydramine and to wait until its effects have fully worn off.

Is Benadryl worse than alcohol for driving?

In a driving simulator study, a single 50 mg dose of diphenhydramine impaired driving more than a blood alcohol level of 0.10, and the authors concluded it may have an even greater impact than alcohol. Never drive after taking Benadryl.

Can I take Benadryl to sleep after drinking?

It is not recommended. Both are sedating, alcohol disrupts sleep, and the combination can cause heavy grogginess and, at higher doses, slowed breathing.

What happens if you mix Benadryl and alcohol?

You may feel heavily drowsy, dizzy, confused, or uncoordinated, and your reaction time and judgment will be impaired, even if you do not feel sleepy. Serious cases can involve slowed breathing.

Is it safe to take Benadryl for an alcohol flush or reaction?

Do not self-treat repeated reactions to alcohol. See a clinician to find the cause, and never combine antihistamines with alcohol. For a severe reaction with trouble breathing, call 911 and use epinephrine if you have it.

What is the FDA warning about Benadryl?

In 2020, the FDA warned that taking higher than recommended doses of diphenhydramine can cause serious heart problems, seizures, coma, or death, after reports linked to the “Benadryl Challenge.”

Are there sleep aids that do not have this warning?

All sedating sleep products deserve caution with alcohol. Many over-the-counter sleep aids contain diphenhydramine, and others contain doxylamine, which has a similar effect. Read the label, and talk to a clinician about better long-term options.

Can older adults take Benadryl?

Doctors generally advise caution or avoidance in older adults, because first-generation antihistamines can cause confusion, falls, and urinary retention. Ask your doctor.