Pet placebo?
Posted: Wed Feb 11, 2026 5:50 pm
My wife obtains these non-prescription capsules called Zylkene, made by a firm called Vetoquinol. They are advertised as reducing anxiety in companion animals. The cat is given them for a few days before we take her on a journey in the car. Although also labelled in English, they are mainly sold in Czech and Slovakia, which is where she buys them. The same product is sold for cat and dog, the only difference being the quantity in the capsules.
The ingredients are clearly labelled: maltodextrin, casein and magnesium stearate.
This looks like a placebo to me. But can placebos work on non-human animals? To get the cat to eat them, we have to open the capsule and scatter the powder on her food. So is the cat even aware she is taking them? Perhaps they taste of something. But it doesn't affect her eagerness to eat her cat food. Cat food has special smell and flavour substances added to it, that makes it very attractive to cats, but disgusting to humans. Can you taste a little bit of maltodextrin, etc, through that?
Perhaps the target of the placebo is actually the owner. We might propose a mechanism similar to "audiophile" products. With those, you do something that you have been told will improve the sound of your hifi, though frequency sampling shows no objective difference. But by drawing your attention to it, and sequential testing, you magically perceive that it has improved with the treatment. Here we hope to perceive that the pet is calmer than she otherwise might be on a car trip. She usually calms down eventually. After an hour or two in the car.
The ingredients are clearly labelled: maltodextrin, casein and magnesium stearate.
This looks like a placebo to me. But can placebos work on non-human animals? To get the cat to eat them, we have to open the capsule and scatter the powder on her food. So is the cat even aware she is taking them? Perhaps they taste of something. But it doesn't affect her eagerness to eat her cat food. Cat food has special smell and flavour substances added to it, that makes it very attractive to cats, but disgusting to humans. Can you taste a little bit of maltodextrin, etc, through that?
Perhaps the target of the placebo is actually the owner. We might propose a mechanism similar to "audiophile" products. With those, you do something that you have been told will improve the sound of your hifi, though frequency sampling shows no objective difference. But by drawing your attention to it, and sequential testing, you magically perceive that it has improved with the treatment. Here we hope to perceive that the pet is calmer than she otherwise might be on a car trip. She usually calms down eventually. After an hour or two in the car.