The following foods may be dangerous to your pet:

Alcoholic beverages
Apple seeds
Apricot pits
Avocados—toxic to birds, mice, rabbits, horses, cattle and dairy goats
Cherry pits
Candy (particularly chocolate, which is toxic to dogs, cats and ferrets, and any candy containing the sweetener Xylitol)
Coffee (grounds, beans, chocolate covered espresso beans)
Grapes
Hops (used in home beer brewing)
Macadamia nuts
Moldy foods
Mushroom plants
Mustard seeds
Onions and onion powder
Peach pits
Potato leaves and stems (green parts)
Raisins
Rhubarb leaves
Salt
Tea (caffeine)
Tomato leaves and stems (green parts)
Walnuts
Yeast dough

These are listed from hsus.org (Humane Society of United States)

Hi - I see on the list that tomatoes are not good for cats. My cats love them, but only get a few diced pieces at a time. I don’t feel that vegetables in large amounts would be good for them, as they are carivores by nature. The one cat even loves (drives me crazy begging when I use it) lettuce, plain. I figure as he is a house cat, perhaps it is like an outdoor cat cating grass?

Thanks for the great information -

J McCartan

When I was growing up, all our cats loved my mom’s green beans!  They always had oregano, onion, garlic, and bacon grease in them.  It was probably the bacon grease that interested them.  Looking back, I’m surprised that the onion and garlic didn’t cause any problems, but it never seemed to.  The garlic was powdered, and the onions were dehydrated (and usually left behind in the bowl when the cats were done).  Perhaps it was a small enoough amount that it made no difference. Feeding the cats whatever leftovers they would consume was my family’s practice for about 20 years.  These leftovers were considered treats to moisten their kibble once a day; the rest of the time they ate it dry.  Once a week they got a can of tuna, as my mother believed the oil in it cleared out hairballs. Anyhow, all the leftovers were generously seasoned, but our cats were very healthy.  Of course, few lived longer than 2 or 3 years because they got run over in those free-running days.  Perhaps if they had lived longer, we’d have seen negative results from eating the onions, garlic, and other spices.