Source of information: Cornell University Poisons, Medicines and Dangerous Plant Database

In spite of your best efforts, your animal may accidentally become poisoned. Being prepared can save your pet’s life. Know your vet’s procedures for emergency situations, especially ones that occur after business hours. Keep phone numbers for your veterinarian, the RSPCA Animal Poison Control Centre and a local emergency veterinary service in a convenient location.
Keep a dog poison safety kit on hand for emergencies.

Your kit should contain:
A fresh bottle of hydrogen peroxide 3% (USP).
Can of wet dog food.
Turkey baster, bulb syringe or large medical syringe.
Saline eye solution to flush out eye contaminants.
Artificial tear gel to lubricate eyes after flushing.
Mild grease-cutting washing-up liquid for the animal after skin contamination.
Rubber gloves.
Forceps to remove stingers.
Muzzle (Remember, an excited animal may harm you).
Dog carrier.

If you know what substance your dog has ingested, have the product container/packaging available for reference. You’ll also need to provide information, if you know it, about the amount ingested and the time since exposure.
Your dog’s, breed, age, sex and weight.
All symptoms your pet is experiencing.

Do not feed your pet anything that you think is off, i.e. past its use by date.

Foods to Avoid Feeding Your Dog.
Alcoholic beverages.
Avocado.
Chocolate (all forms).
Coffee (all forms).
Fatty foods.
Macadamia nuts.
Mouldy or spoiled foods.
Onions, onion powder.
Raisins and grapes.
Salt.
Yeast dough.
Garlic.
Products sweetened with xylitol.

Warm Weather Hazards
Animal toxins—toads, insects, spiders and snakes.
Blue-green algae in ponds.
Citronella candles.
Cocoa mulch.
Compost piles.
Fertilisers.
Flea products.
Outdoor plants and plant bulbs.
Swimming-pool treatment supplies.
Fly baits containing methomyl.
Slug and snail baits containing metaldehyde.

Medication: Common examples of human medications that can be potentially lethal to dogs, even in small doses, include:
Pain killers.
Cold medicines.
Anti-cancer drugs.
Antidepressants.
Vitamins.
Diet pills.
Cold weather hazards.
Antifreeze.
Liquid potpourri.
Ice melting products.
Rat and mouse bait.

Common Household Hazards.
Fabric softener sheets.
Mothballs.

Holiday Hazards.
Christmas tree water (may contain fertilizers and bacteria, which, if ingested, can upset the stomach.
Electrical cords.
Ribbons or tinsel (can become lodged in the intestines and cause intestinal obstruction—most often occurs with kittens!)
Batteries.
Glass ornaments.

Non-toxic Substances for Dogs. The following substances are considered to be non-toxic, although they may cause mild gastrointestinal upset in some animals:
Water-based paints.
Toilet bowl water.
Silica gel.
Poinsettia.
Cat litter.
Glue traps.
Glow jewellery.

Other potential dangers.
Pear pips, the kernels of plums, peaches and apricots, apple core pips (contain cyanogenic glycosides resulting in cyanide poisoning) Potato peelings and green looking potatoes Rhubarb leaves mouldy/spoiled foods Alcohol Yeast dough Coffee grounds, beans & tea (caffeine) Hops (used in home brewing) Tomato leaves & stems (green parts) Broccoli (in large amounts) Raisins and grapes Cigarettes, tobacco, cigars.

The following are poisonous to your dog.
Never give paracetamol based (toxic to liver) or ibuprofen. Ibuprofen is very toxic and fatal to dogs at low doses. Only aspirin is safe for dogs and buffered aspirin is preferred to minimise stomach upset.

Ointments containing zinc can cause stomach irritation in dogs.

Mosquito and lice sprays formulated for humans are toxic if applied to dogs (because they are likely to lick themselves and ingest the DEET or permethrin).

Onion and garlic poisoning.
Onions and garlic contain the toxic ingredient thiosulphate. Onions are more of a danger.
Dogs affected by onion toxicity will develop haemolytic anaemia, where the dog’s red blood cells burst while circulating in its body.

At first, dogs affected by onion poisoning show gastroenteritis with vomiting and diarrhoea. They will show no interest in food and will be dull and weak. The red pigment from the burst blood cells appears in an affected dog’s urine and it becomes breathless. The breathlessness occurs because the red blood cells that carry oxygen through the body are reduced in number.

The poisoning occurs a few days after the dog has eaten the onion. All forms of onion can be a problem including dehydrated onions, raw onions, cooked onions and table scraps containing cooked onions and/or garlic. Left over pizza, Chinese dishes and commercial baby food containing onion, sometimes fed as a supplement to puppies, can cause illness. Onion poisoning can occur with a single ingestion of large quantities or with repeated meals containing small amounts of onion. A single meal of 600 to 800 grams of raw onion can be dangerous whereas a ten-kilogram dog, fed 150 grams of onion for several days, is also likely to develop anaemia. The condition improves once the dog is prevented from eating any further onion.
While garlic also contains the toxic ingredient thiosulphate, it seems that garlic is less toxic and large amounts would need to be eaten to cause illness.

 Plants and foods that are toxic to dogs.

Almonds
Amaryllis bulb
Apricot
Autumn crocus ( Colchicum autumnale)
Avocado (leaves, seeds, stem, skin)
Azalea (entire rhododendron family)
Begonia
Bird of Paradise
Bittersweet
Bleeding heart
Boxwood
Bracken fern
Buckeye
Buttercup (Ranunculus)
Caffeine
Caladium
Calla lily
Castor bean* (can be fatal if chewed)
Cherry
Chinese sacred or heavenly bamboo
Chocolate
Choke cherry (unripe berries)
Chrysanthemum (a natural source of pyrethrins)
Clematis
Crocus bulb
Croton (Codiaeum sp.)
Cyclamen bulb
Delphinium, larkspur, monkshood
Dumb cane (Dieffenbachia)
Elderberry (unripe berries)
English ivy (All Hedera species of ivy)
Fig (Ficus)
Four-o’clocks (Mirabilis)
Foxglove (Digitalis)
Garlic
Hyacinth bulbs
Hydrangea
Holly berries
Iris corms
Jack-in-the-pulpit
Jimson weed
Kalanchoe
Lantana
Lily (bulbs of most species)
Lily-of-the-valley
Lupine species
Milkweed
Mistletoe berries
Morning glory
Mountain laurel
Narcissus, daffodil (Narcissus)
Oak.
Oleander
Onions
Peaches
Pencil cactus plant* (Euphorbia sp.)
Philodendron (all species)
Poinsettia (many hybrids, avoid them all)
Potato (leaves and stem)
Rhubarb leaves
Rosary Pea (Arbus sp.) (Can be fatal if chewed)
Scheffelera (umbrella plant)
Shamrock (Oxalis sp.)
Spurge (Euphorbia sp.)
Tomatoes (leaves and stem)
Yew