It is dangerous and potentially fatal to give Benadryl (diphenhydramine) to horses. Horses metabolize medications differently than humans, and even small doses of Benadryl can be toxic to them.
Here's what you should do:
1. Contact your veterinarian immediately. They are the only ones qualified to diagnose your horse's condition and recommend the appropriate treatment.
2. Describe your horse's symptoms clearly. This will help your veterinarian understand the situation.
3. Follow your veterinarian's instructions. Never give your horse any medication without consulting your veterinarian first.
Possible causes of watery eyes and nose in horses:
* Allergies: Pollen, dust, or other allergens can trigger these symptoms.
* Infections: Viral, bacterial, or fungal infections can cause inflammation of the eyes and nasal passages.
* Dental problems: Infections in the teeth or gums can cause nasal discharge.
* Other: Certain medical conditions, such as Cushing's disease, can also cause watery eyes and nose.
Remember, your veterinarian is the best resource for ensuring your horse's health and safety.