My 1st time placing an order with Koala was so convenient & made my almost 5 yr. old Lil'bit (Cat) energized & back to being herself. The Nexguard Combo, which I had never tried started working almost immediately. The only problem we had was @ first in the shipping dept. We all noticed (myself & Koala Health) that the tracking just stopped. Well, as I desperately needed the meds, Koala sent out a new package & I received it within a few days. They really care about our fur babies, so if anyone has questions, please don't hesitate to call, message or order from Koala.