Certified GKH Gardening Expert
These are highly toxic to cats. Please do not allow you cat to chew on houseplants, as many that are harmless to us are deadly to cats.
Cats are carnivorous, and will chew on plants if their nutrient requirements are not met, and out of boredom.
If your cat is doing this, you may look to changing foods, and finding out what nutrient the cat is lacking, as this is a dangerous thing with many houseplants.
Hostas contain saponin which can cause mild to severe stomach and intestinal distress, depending on how much is consumed. It is always wise to check with your vet. There are also online pet websites that list the most toxic plants. Hostas are not on the top 10 list of most toxic plants to cats.