Dogs and Bee Stings
If you dog likes to chase bees, it's likely that they will eventually get stung. If your dog has an allergic reaction you can use Benadryl ( diphenhydramine hydrochloride ) orally.
Call your vet and they will tell you the proper dosage. Your dog might either get sleepy or hyper after adminstering the drug (just like small children do).
This works great if your dog is just swollen or irritated from the sting, but if she is having difficulty breathing after a sting, it's best to take her to a vet where they will inject Benadryl directly into her system.