I too have a lot of house plants but the cats in the past and the present have never wanted to eat them except for the spider plant. and they have never been harmed by the spider plant (20 or more odd years of cats). A couple of the cats loved playing with hibiscus flowers. they didnt eat them, just played with them like catnip. They would even strip the bud from the tree. I too have cat grass growing occasionally, I am sure I read it was oat seeds but I could be wrong and am too lazy to check the packaging. I sprinkle parsley on Lynx's food occassionally for general health and also for breath. Occasionally he will vomit but not all the time. Enzo the cat from next door (I have 1.25 cats.....lol) also eats the cat grass, chews on the spider plant and like Lynx is seems to like catnip occasionally. I have tried to grow catnip but some how it just doesnt grow.