My Yorkie is 6.1 pounds and 8 months old. She started SimparicaTrio in March 2021. For three months my dog has had diarrhea that begins 3-5 days after I give her the flea/tick medicine. When your vet recommends this medicine what is a pet owner to do but give the med. This is expensive and I do not like paying for a medicine that could possibly kill my Yorkie. I am pissed, damn right I am! Do not be a victim! The medicine is Simparica Trio Chew tab for fleas and ticks. User's recommendation: Do not use this flea/tick medicine on your pets.