How to Induce Vomiting (and when not to):
DO NOT induce vomiting if your cat has swallowed an acid or other corrosive.  Symptoms of such poisons include sores on your cat's mouth, a swollen mouth or tongue, and burns arounf the mouth, lips and tongue.  In such a case, if your cat is conscious, encourage her to take in as much milk or water as she will drink to dilute the poison.

Vomiting can be introduced by giving your cat one teaspoon of a 3 per cent hydrogen peroxide solution every ten minutes.  One fourth of a teaspoon of table salt placed at the back of the tongue or mixed in one tablespoon of water is also effective.  Also good for inducing vomiting is syrup of ipecac:  one teaspoon per 10 pounds of body weight.  If your cat doesn't vomit within thirty minutes, try it again.  (Hydrogen peroxide is most effective.)

When your cat has finished vomiting, give her one heaping teaspoon of activated charcoal tablets (available in drugstores) dissolved in one ounce of water.  Characoal absorbs many poisons.  Thirty minutes later, give your cat Milk of Magnesia or Kaopectate, one teaspoon per five pounds of body weight.