Hi and thank you. The product goes by the name of Purina GoCat here. The biscuits come in a variety of flavours and the one in question here is chicken/duck/rabbit but I've also had other flavours with the same results. Gocat is a big brand name here in the UK. The box claims "100% complete nutrition". I was also giving my cats wet food but I can guarantee this stuff makes them bring up anything else within hours.
Thank you again this means so much :)
Some of the ingredients of our pets foods are pretty dang scary and with dire consequences as you have seen first hand. Many of these contain meat &/or other additives from China that are questionable.
Tell us the name of the product, brand &/or ingredients. Don't know if the same one is avail here in US or Canada, if they are I will find some info for you, just may take a few days I'm kinda bogged down rt now.
Canned food is always a much preferred diet for cats especially:)