As previously stated, it is clear to see that a dosage of Benadryl is highly dependent on a dog’s weight. As an individual who owns a dog for pet, it is highly advisable for you to first take your dog to a certified vet who has the right kind of knowledge and expertise when it comes to administering the right Benadryl dosage for dogs. Taking anything less of a full dose will not help in any way while taking an overdose is considered to be quite dangerous. A veterinarian will also be able to conclude on the right frequency when it comes to administering the drug. This can either be after every four, eight or even twelve hours. More importantly the vet will also ask various probing questions which will help him come to a conclusion as to whether or not your pet dog is suffering from an allergic reaction or something totally different.