Standard Benadryl tablet strength
Most over-the-counter Benadryl tablets sold in the United States contain 25 milligrams (mg) of diphenhydramine hydrochloride per tablet. This is the standard dose you will find in regular Benadryl boxes at drugstores and supermarkets.
Benadryl also makes other formulations with different strengths. Some liquid gels and capsules also contain 25 mg, while children's formulations are weaker. The strength printed on the front of the box tells you what is inside, so always check the label before taking anything.
If you are taking Benadryl for the first time, start with one tablet and see how your body responds. Do not assume all antihistamine tablets are the same strength — different brands and different products within the same brand can vary.
Key Takeaways
- Standard over-the-counter Benadryl tablets contain 25 mg of diphenhydramine per tablet.
- Always read the label on your specific box, because some Benadryl products contain different strengths or different active ingredients.
- The typical adult dose is one tablet every four to six hours, but you should not exceed six tablets in 24 hours without talking to a doctor or pharmacist.
- Children's Benadryl products are formulated at lower strengths and require dosing by weight, not by age alone.
- If you are taking other medications or have health conditions, ask a pharmacist whether Benadryl is safe for you before taking it.
How to read the label on your Benadryl box
The front of a Benadryl box clearly states the strength in milligrams. Look for text that says "25 mg" or similar. The label also lists the active ingredient — for regular Benadryl, this is diphenhydramine hydrochloride. Some Benadryl products use a different active ingredient called acrivastine, which has a different strength.
The back of the box contains the dosing instructions. This tells you how many tablets to take at once and how often you can take them. The label also lists warnings and tells you which groups of people should not take the product — for example, pregnant women or people with certain medical conditions.
If the label is hard to read or you cannot find the strength listed, ask the pharmacist at the counter. They can tell you exactly what is in the box and whether it is the right product for what you need.
Typical dosing for adult Benadryl tablets
The standard dose for an adult is one 25 mg tablet every four to six hours as needed. Most people take it when they feel an allergic reaction starting or when they need help sleeping. You should not take more than six tablets in a 24-hour period without talking to a doctor.
Dosing depends on why you are taking it. For allergies, you might take one tablet and wait to see if it helps. For sleep, you might take one tablet 30 minutes before bed. The label on your box will give you specific guidance for your situation.
If you find that one tablet is not working after an hour, do not when ready take another one. Wait the full four to six hours before your next dose. Taking more tablets sooner than the label says can cause side effects like extreme drowsiness, dry mouth, or dizziness.
Benadryl products with different strengths
While 25 mg is the most common strength for regular Benadryl tablets, the company makes other products. Benadryl Extra Strength contains 50 mg per tablet or capsule. Benadryl Children's formulations are much weaker — typically 12.5 mg per 5 milliliters of liquid — and are dosed by the child's weight, not by age.
Some Benadryl products are combination formulas that include other active ingredients like acetaminophen or ibuprofen for pain relief. These have different strengths and different dosing rules. Always look at what the box says the product is for and what active ingredients it contains.
Generic diphenhydramine tablets sold under store brands also typically contain 25 mg, but always verify by reading the label. The price may be lower, but the strength should be the same as name-brand Benadryl.
When to talk to a pharmacist or doctor before taking Benadryl
Before taking any Benadryl product, tell a pharmacist or doctor if you are pregnant, breastfeeding, or have any of these conditions: glaucoma, heart disease, high blood pressure, thyroid problems, diabetes, or difficulty urinating. Benadryl can interact with these conditions or make them worse.
If you are taking other medications — including prescription drugs, other over-the-counter products, or supplements — ask a pharmacist whether Benadryl is safe to combine with them. Diphenhydramine can interact with sedatives, antidepressants, and blood pressure medications.
Older adults sometimes have stronger reactions to antihistamines and may need a lower dose or a different product. If you are over 65, ask a pharmacist for guidance before starting Benadryl.
Side effects and what to expect
The most common side effect of Benadryl is drowsiness. Many people take it specifically for this reason when they need help sleeping. Other common side effects include dry mouth, blurred vision, and constipation. These usually go away as your body adjusts.
Some people experience the opposite effect — restlessness or difficulty concentrating — instead of drowsiness. If this happens, do not drive or operate machinery. Stop taking the product and talk to a doctor if the reaction is severe.
Serious side effects are rare but can include rapid heartbeat, difficulty urinating, or confusion. If you experience any of these, stop taking Benadryl and contact a doctor or poison control when ready. In the United States, poison control can be reached at 1-800-222-1222.
Storage and expiration of Benadryl tablets
Store Benadryl tablets at room temperature, away from heat and moisture. Keep them in the original box or a closed container so you can always see the label and dosing instructions. Do not store them in the bathroom, where humidity from showers can break down the medication.
Check the expiration date on the box before taking a tablet. Expired medication may not work as intended and could potentially be harmful. If your Benadryl has expired, throw it away safely — many pharmacies have medication disposal programs where you can drop off old pills for free.
Keep Benadryl out of reach of children and pets. Even though children's formulations exist, adult-strength tablets can be dangerous if a small child takes them by accident.
Frequently Asked Questions
Can I take more than one Benadryl tablet at a time?
The label says to take one tablet every four to six hours, not multiple tablets at once. Taking more than one tablet at a time increases the risk of side effects like extreme drowsiness or dizziness. If one tablet is not working, wait the full four to six hours before taking another dose, or talk to a pharmacist about whether a different product might work better.
Is Benadryl safe to take every night for sleep?
Using Benadryl regularly for sleep is not recommended by most doctors. Your body can build up a tolerance, meaning it stops working as well over time. If you are having ongoing sleep problems, talk to a doctor about longer-term solutions instead of relying on antihistamines every night.
What is the difference between 25 mg and 50 mg Benadryl?
The 50 mg version (Benadryl Extra Strength) contains twice as much diphenhydramine as the regular 25 mg tablet. It is stronger and may cause more drowsiness. Do not take both a regular and an extra-strength tablet together, as this would exceed safe dosing limits.
Can I take Benadryl with alcohol?
No. Alcohol and Benadryl both cause drowsiness and can slow your reaction time. Taking them together increases the risk of extreme drowsiness, dizziness, and impaired judgment. Do not drink alcohol while taking Benadryl or for several hours after taking a dose.
What should I do if I accidentally take too much Benadryl?
If you or someone else has taken more Benadryl than the label recommends, contact poison control at 1-800-222-1222 or go to an emergency room. Have the box with you so you can tell them the exact strength and how many tablets were taken. Do not wait to see if symptoms develop.