Question: how much diphenhydramine can you take at one time?
Answer: Typical doses for Benadryl are: For adults and children older than 12, take 1 to 2 tablets or capsules every 4 to 6 hours as needed. For children ages 6 to 11, take 1 tablet or capsule every 4 to 6 hours as needed, or 1 to 2 teaspoons of Benadryl liquid every 4 to 6 hours as needed.