Why Dogs Eat Grass and Other Animals Who Use Herbal Medicine

A lot of dogs eat grass. Some eat grass then regurgitate it. Others let the grass work its way through their system. And while there is a lot of debate about exactly why dogs eat grass, it's almost certainly as a herbal medicine.

Dogs lack the enzymes to digest grass, so there is no nutritional value to them in eating it. If we look at the way some other animals treat certain plants in their environments, we start to see a picture of animals self-medicating. This phenomenon is called zoopharmacognosy, and it's a fairly new discipline of science that is investigating how animals use plants as medicine and whether there are any implications for humans.

Getting Rid of Parasites

Perhaps the dogs eating grass are doing what some ape species do when they have gut parasites - worms. They eat certain rough leaved plants that effectively clear out these internal parasites.

Some suggestions about our canine friends nibbling the green stuff centre around gastrointestinal issues. Perhaps these dogs know to eat grass when they have a tummy upset, to help settle their stomach.

Butts in the Nest

Scientists have seen some urban birds incorporate cigarette butts into their nests, using the residual nicotine as a deterrent for certain parasites. Scientists have even discovered certain insects - such as moths and caterpillars - who also use herbal medicine.

The Right Dose

It seems the animal kingdom doesn't only know which plants to use for which conditions, but they are also clever enough not to over-dose themselves. Many plants can be toxic in large doses, while their medicinal properties are most effective at a certain amount. How do the animals know this - whether they learn it from each other, passing the knowledge down from generation to generation, or experiment with it themselves, or in the case of insects whether it's an instinct - we have yet to fully explore.

What we do know is that animals have been "studying medicine" for as long as the human race, perhaps longer. Let's hope there are some useful insights that can also apply to human health.