Works with milkbones or any similar sized treat for larger dog (perfect size for my parents lab). We started by putting kibble in it, which the lab easily figured out you just tip the toy over and there's the food. When we put a milkbone instead she had to chew a bit to get it out. I haven't tried it with whipped cream or peanut butter yet but I imagine they'd be chewing a while in that case. It has grooves which i suppose are designed for tooth brushing.