

Some of the foods that are harmless to humans can be poisonous or otherwise dangerous to dogs. If you want to give your dog some leftovers from the dinner table, make sure the scraps are safe for the dog to eat.
In addition to poisoning, some foods can damage the dog's body in the long term.
Alcohol
A dog's body cannot tolerate alcohol at all; even small quantities can damage the liver. The poisoning symptoms are the same as with any other poisoning.
Avocado
For dogs the most dangerous part of an avocado is the pit, which can cause intestinal obstruction if swallowed. The dog can’t digest the pit. If it blocks the dog’s stomach or intestines partially or completely, the dog needs urgent medical care. Also, avocados contain persin, which is toxic to many animals. Especially high doses of persin can cause poisonous for dogs.
Baking yeast and yeast-containing dough
If you are baking anything that needs yeast to rise, remember to keep the dough away from the dog. If the dog eats the yeast-containing dough, it can expand painfully in the dog’s stomach. Yeast also releases ethanol, which is very dangerous for dogs.
Caffeine
Coffee, tea, and cola drinks usually contain caffeine. Some dogs are very sensitive to caffeine, but others can tolerate small amounts of it. Caffeine increases the dog’s heart rate and can cause cardiac arrhythmias, hyperactivity, vomiting and diarrhea. The dog can get serious poisoning by consuming high amounts of caffeine.
Chocolate
Chocolate is made from cocoa that contains theobromine, a toxin for dogs. Dark chocolate is the most dangerous kind of chocolates since it has the highest theobromine levels, and even a small amount of very dark chocolate can be poisonous. Nevertheless, any kind of chocolate and cocoa powder should be kept away from the dog.
Cooked bones
If you want to give bones to your dog, make sure they are raw or choose commercial chewbones. When the bones are cooked their structure changes. Hence, cooked bones can be extremely sharp and damage the dog’s digestive tract. Both raw and cooked bones carry the risk of suffocation, stomach issues and even intestinal blockage. Keep these risks in mind if feeding your dog raw bones and don’t leave the dog alone with a bone.
Garlic
Like other onions, also garlic contains substances which can lead to anemia. The only acceptable form of garlic for dogs is Aged Garlic Extract (AGE) that has been produced by enzymatic maturing and doesn't contain the harmful tiosulphates.
Grapes and raisins
The toxic amount of raisins and grapes are not known, so the safest decision is not to give any of them to the dog. Grapes and raisins can cause poisoning symptoms and damage the dog’s kidneys.
Macadamia nuts
Some pastries can contain macadamia nuts, which are toxic for dogs. Be causes with other nuts as well.
Medicine for humans
Only give your dog medicines prescribed by a veterinarian. The metabolism of a dog is different from humans, and the intestinal organs of a dog can't process drug molecules like human organs do. For example, a common drug Ibuprofen is very toxic to dogs. Consult your vet first if the dog needs painkillers or other medication.
Milk
Most adult dogs can’t digest the lactose from dairy. Hence, drinking milk can cause abdominal pain and diarrhea.
Onion
Large quantities of onions in any form, raw, cooked, or dried, can cause anemia and typical poisoning symptoms to dogs. Anemic changes can develop in a few days. A dog suffering from anemia can show symptoms like mucous membranes turning light or yellow, breathing difficulties, dark urine, and general weakness.
Xylitol
In a dog's body, xylitol causes excessive insulin secretion, resulting in a drastic drop of blood glucose. This leads to a hypoglycemic shock that causes cramps. Besides possible poisoning symptoms, xylitol can cause liver damage to dogs. So, make sure the dog won’t eat any chewing gum or pastilles that contain xylitol.
Some dogs tend to chew and eat objects that are not intended for chewing nor eating. For example, a swallowed sock, too big piece of a bone, plastic wrappings from the trash or parts of a toy can block the dog’s bowel.
Intestinal blockage is a life-threatening condition that requires immediate medical attention since it can lead to necrosis of intestinal tissue and other serious complications.
Always contact your vet, if you suspect your dog has eaten something poisonous or a foreign / sharp object.