Onions and garlic

Garlic, onions, and leeks are part of the allium plant family, which can break down red blood cells in canines. This can cause your dog to become anemic.

Peaches, plums, and persimmons

Most obviously, the pits can cause intestinal blockages that can turn serious. However, the pits also contain cyanide, which is toxic to humans and pets alike.

Yeast

Yeast in any form before it’s baked is extremely dangerous for your dog, as it will continue rising in their stomach. Ingestion of yeast dough can cause gas to accumulate in your dog’s digestive system as a result of the dough rising.  Not only can this be painful but it may also cause the stomach or intestines to become obstructed (blocked) or distended.

Grapes and raisins

Eating these otherwise innocuous snacks can cause severe liver damage.

Alcohol

Alcohol has the same effect on a dog’s liver as it does with humans, but it takes far less to do the same damage. Just a little can cause vomiting, diarrhea, central nervous system depression, problems with coordination, difficulty breathing, coma, even death.

Candy and gum

Both will often contain a sweetener called xylitol, which is also found in toothpaste and some diet foods. In dogs, xylitol can lead to an insulin spike, which ultimately is bad for blood sugar and can potentially cause damage to the liver.

Macadamia nuts

As few as six macadamia nuts can make your canine ill, whether they’re raw or roasted. The poisoning can become apparent through muscle tremors, vomiting, and even paralysis. Symptoms might only last for 12 to 48 hours after ingestion, depending on the dosage, but you should take it very seriously if your dog accidentally eats even a handful of these nuts.

Corn on the cob

A chunk of corn cob that’s even just a few inches can be enough to cause a problem and can apparently be quite difficult to locate on X-rays. In the worst cases, eating corn cobs can land your canine in surgery.

Caffeine

Caffeine contains substances called methylxanthines, which are found in the fruit of the plant used to make coffee, and in the nuts of an extract used in some sodas. When ingested by pets, methylxanthines can cause vomiting and diarrhea, panting, excessive thirst and urination, hyperactivity, abnormal heart rhythm, tremors, seizures and even death.

Chocolate

Like caffeine, chocolate contains methylxanthines, and can carry the same dangerous side effects as caffeine. All types of chocolate contain these compounds, though it’s more prevalent in some kinds. Dark chocolate, chocolate mulch, and unsweetened baker’s chocolate are particularly potent and harmful to dogs.