Itching / Allergies

Dosages for Diphenhydramine (Benadryl) for different weights

Medicine Name: Diphenhydramine (Benadryl) May Give Every 20/24 lbs. 25-37 lbs. 38-49 lbs. 50-99 lbs. 100+ lbs.
Liquid 12.5 mg/ 1 teaspoon (tsp) 6-8 hours 3/4 tsp. 1 tsp. 1-1/2 tsp. 2 tsp. -
Liquid 12.5 mg/ 5 milliliters (mL) 6-8 hours 4 mL 5 mL 7.5 mL 10 mL -
Chewable 12.5 mg 6-8 hours - 1 tab. 1-1/2 tab. 2 tab. 4 tab.
Tablets 25 mg 6-8 hours - 1/2 tab. 1/2 tab. 1 tab. 2 tab.
Capsules 25 mg 6-8 hours - - - 1 cap. 2 cap.

When to Use. Treatment of allergic reactions, nasal allergies, hives and itching.

Table Notes:

  • AGE LIMITS. For allergies, don't use under 1 year of age. (Reason: it causes most babies to be sleepy). For colds, not advised at any age. (Reason: no proven benefits). They should be not be given if under 4 years old. If under 6 years, don't give products with more than one ingredient in them. (Reason: FDA recommendations 10/2008).
  • DOSE. Find the child's weight in the top row of the dose table. Look below the correct weight for the dose based on the product you have.
  • MEASURE the DOSE. Syringes and droppers are more accurate than teaspoons. If possible, use the syringe or dropper that comes with the medicine. If not, you can get a med syringe at drug stores. If you use a teaspoon, it should be a measuring spoon. (Reason: regular spoons are not reliable.) Keep in mind 1 level teaspoon equals 5 mL and that ½ teaspoon equals 2.5 mL. 
  • ADULT DOSE. 50 mg
  • HOW OFTEN. Repeat every 6 hours as needed.
  • CHILDREN’S BENADRYL FASTMELTS. Each fastmelt tablet equals 12.5 mg. They are dosed the same as chewable tablets.

Customized from Itching Allergies v0.1 7/8/2025