Spot came to see us as an emergency one weekend because he had suddenly gone blind and was showing neurological abnormalities. Once Dr. Beaumont performed her examination, she could see abnormal changes in his retinas. At this point, Dr. Beaumont thought that Spot's acute onset of blindness might be caused by an infectious disease or an auto-immune issue. We re-examined him 2 days later and his vision and neurological abnormalities were much improved, but we didn't expect him to improve so much so quickly. A few days later we learned that Spot's owners had dewormed over 20 horses with ivermectin the day before he started showing symptoms. Spot has a history of eating horse feces and his symptoms were not the typical signs of an auto-immune disorder or an infectious disease. We rechecked Spot again 1 week later and he was completely back to normal! He had regained all of his vision and was acting like his normal self! We were able to rule out an infectious disease and auto-immune disorder based on bloodwork and his rapid improvement. Spot's temporary blindness and neurologic symptoms were most likely due to ivermectin toxicity (from eating horse feces after the horses had been dewormed). Spot is doing great and is back to helping his owners take care of the ranch.