Here is a great article from Cornell on Common Cat Hazards!!
Common Cat Hazards
Indoor and outdoor plants can pose a risk to your cat. Ingesting just a small piece of some common ornamental plants such as poinsettias could be enough to make a cat ill, and swallowing a sizable amount could prove fatal. Lilies are especially toxic to cats; they can cause life-threatening kidney failure if ingested even in tiny amounts.
Plants that are toxic for cats include (but are not limited to):
Many of the chemicals around your house can present a hazard for your feline friends. Keep these materials in a place your cats can’t reach, and ensure any spills are cleaned up promptly. If you have an outdoor cat, take precautions when using these products in your yard.
Molluscicides (snail baits and snail pellets)
Ethylene glycol antifreeze
Swimming pool chemicals
Household cleaners (including bleach, detergents, and disinfectants)
It’s tempting to give your beloved cat a treat of human food, but many of the things we enjoy are off-limits for our feline friends, including:
Anything containing xylitol, an artificial sweetener
Human medications and flea treatments for dogs can be acutely toxic for cats. Remember: never give your cat medications without first consulting your veterinarian. Cats will often gobble up pills they find lying on tables or dropped on the floor, so be vigilant with your medications.
Some common causes of poisoning include:
Dietary supplements (vitamins)
Flea medication for dogs (Cats must not be allowed to come in contact with a treated dog for 24 hours)
Some Common Signs of Poisoning Include:
Blood in the stool/urine
Loss of appetite
Inability to urinate
How Quickly Will My Cat Become Ill?
This depends upon the toxin involved. By the time an owner recognizes a problem, a cat may be at significant risk for serious health problems. For this reason, a prompt veterinary consultation is essential.
What Should I Do If I Think My Cat Has Ingested Something Toxic?
Call your veterinarian immediately. If your vet is not available, try a local emergency veterinary clinic or animal poison control help hotline (see below).
If you are aware of the toxin that your cat was exposed to, obtain a sample or a label to bring to the veterinarian or to provide information to a help hotline.
IMPORTANT: DO NOT induce vomiting unless you are specifically directed to do so. Certain poisons can cause more damage during vomiting than if left in the stomach.
Pet Poison Helpline 855-289-0358
ASPCA Animal Poison Control: 888-426-4435