Allergic reactions, hives and itching · Over the counter
Benadryl (diphenhydramine) dosage for children
Also sold as Children’s Benadryl Allergy, generic diphenhydramine
Children’s Benadryl liquid is 12.5 mg per 5 mL. A 25-37 lb child gets 5 mL; a 50-99 lb child gets 10 mL. The package says not to use it under 2, and to use it for ages 2 to 5 only if a doctor directs. From age 6, give a dose every 4 to 6 hours, no more than 6 doses in 24 hours. Don’t use it for colds, and never use it to make a child sleepy.
Source: St. Louis Children's Hospital · Kenvue Brands
Benadryl dose calculator
Benadryl dosage chart
| Weight | Dose (mg) | Liquid 12.5 mg/5 mL | Chewable 12.5 mg | Tablet 25 mg | Capsule 25 mg |
|---|---|---|---|---|---|
| 20-24 lb (9.1-11.3 kg) | 10 mg | 4 mL | not used | not used | not used |
| 25-37 lb (11.3-17.2 kg) | 12.5 mg | 5 mL | 1 tablet | ½ tablet | not used |
| 38-49 lb (17.2-22.7 kg) | 18.75 mg | 7.5 mL | 1½ tablets | not used | not used |
| 50-99 lb (22.7-45.4 kg) | 25 mg | 10 mL | 2 tablets | 1 tablet | 1 capsule |
| 100 lb and up (45.4 kg+) | 50 mg | 20 mL | 4 tablets | 2 tablets | 2 capsules |
- Under 2 years: the package says do not use. Only give it if your child’s doctor tells you to, and ask them for the dose.
- Under 6 years: the package says to use only if a doctor directs you to. Check with your child’s doctor first.
Chart: St. Louis Children's Hospital. A hyphen means that product isn’t used at that weight.
What Benadryl is for, and what it isn’t for
Diphenhydramine treats allergic reactions, hives, itching, and nasal and eye allergy symptoms. It is not recommended for colds at any age, and it should never be used to make a child sleepy. In some children it causes the opposite: agitation and trouble sleeping.
For everyday seasonal allergies, doctors often prefer a once-a-day antihistamine that causes less drowsiness, such as cetirizine (Zyrtec).
Call 911 for a severe allergic reaction
Benadryl does not treat anaphylaxis. If your child has trouble breathing, swelling of the lips, tongue or throat, repeated vomiting after a food, or seems faint, call 911. If your child has an epinephrine auto-injector, use it first.
When an allergic reaction needs a doctor
- Your child is under 2 and has an allergic rash or itching.
- Hives last more than a few days or keep coming back.
- Your child becomes very sleepy, confused, has a racing heart, or seems agitated after a dose.
- You gave too much or aren’t sure. Call Poison Control at 1-800-222-1222.
Common questions
Can I give Benadryl to a 1-year-old?
Only if your child’s doctor tells you to. The package says do not use under 2. More on Benadryl for babies under 2.
Can I give Benadryl to help my child sleep?
No. The package warns against using it to make a child sleepy, and it can cause agitation instead.
How long does Benadryl last?
About 4 to 6 hours in most children, which is why it needs repeat doses. Once-daily antihistamines like cetirizine last up to 24 hours.
Sources
- Diphenhydramine (Benadryl) Dose Table. St. Louis Children's Hospital (Schmitt Pediatric Guidelines). Checked 2026-09-18.
- Children’s Benadryl Allergy (diphenhydramine HCl 12.5 mg/5 mL): Drug Facts. Kenvue Brands, label via DailyMed (revised 24 Jul 2026). Checked 2026-09-25.