Lots of people grow marijuana for medicinal purposes (wink, wink), and some growers have found that their cats chew the leaves and get the same sort of high that human beings get from smoking marijuana. (It doesn’t seem to increase their cats’ appetites, however.) Amusing as this might be to marijuana users (sharing a high with your pet), it is also potentially dangerous, as marijuana has been known to cause seizures, sometimes fatal ones, in cats.