This is in the sick/injured thread stickies:
http://www.yorkietalk.com/forums/sic...g-dosages.html
*6. Antihistarnines:
Benadryl (Diphenhydramine 25 mg Tablets or 12.5 mg/5 ml liquid)
May cause drowsiness or hyper-excitability!
DOGS: 4-8 ml per 10 pounds or 1-2 tablets per 25 pounds orally 2-3 times a day.
CATS: Same dose as for dogs.