Good answer Harley,
Benadryl is a trade name and the drug name is diphenhydramine. It can be used in humans, dogs, cats, horses, cattle, many birds, rabbits, ferrets and some pocket pets. Remember all 'human' medication had to be tested on animals first.
Benadryl is typicaly dosed IN DOGS: at a mg/lb of weight. (or 2.2mg/kg). Before giving, always as your vet though. Also watch the labels to make sure there is no Tylenol or other active ingredients in the medication.
In horses the dose is lower per weight and typically given either as intravenous or intramuscular injection.
Christopher A. Lee, D.V.M., C.V.L.S.
Promoting surgical options and pet comfort through the use of lasers.