Simparica Trio is a prescription medication used for the prevention and treatment of multiple parasitic infections in dogs, including fleas, ticks, and heartworms. In the United States, the medication typically requires a veterinarian's prescription to ensure appropriate use, dosing, and safety. Some pet owners may search for options to obtain Simparica Trio without vet prescription, though this can involve potential legal and health risks. It is crucial to recognize the importance of veterinary oversight when using such treatments, as improper use or incorrect dosages may lead to adverse effects or ineffective parasite control, potentially harming the pet's health.