Grapes kills dogs. Most of the people I know fed grapes as treats before they discovered it can in fact kill them. I go with the "if it's toxic in even small quantities, why risk it?"
Garlic in SMALL doses is not harmful. In large doses it is a problem. Dogs love garlic... many dog foods used it.
From AKC:
How much garlic is toxic to dogs?
Studies have found it takes approximately 15 to 30 grams of garlic per kilograms of body weight to produce harmful changes in a dog’s blood. To put that into perspective, the average clove of supermarket garlic weighs between 3 and 7 grams, so your dog would have to eat a lot to get really sick. However, some dogs are more sensitive to garlic toxicity than others, and consumption of a toxic dose spread out over a few days could also cause problems.<<
https://www.akc.org/expert-advice/nutrition/can-dogs-eat-garlic/
Chocolate in enough doses can and does kill dogs. My friend's retriever stole a bag of miniatures, unwrapped them one by one and ate them all. Big dog, not that much actual chocolate, dog was fine. Just don't share if you can help it.
As for Antigone on dark, you have it entirely backwards.
https://vcahospitals.com/know-your-pet/chocolate-poisoning-in-dogs
Dogs cannot metabolize theobromine and caffeine as well as people can. This makes them more sensitive to the chemicals’ effects.
How much chocolate is poisonous to a dog?
The amount of toxic theobromine varies with the type of chocolate. The darker and more bitter the chocolate, the more dangerous it is to dogs. <<
@roojuice
Please trust your vet.
And eucalyptus oil is definitely not good for dogs. The craze in the US for diffusers has resulted in a lot of dogs being poisoned. As a general rule, always check with dog poison sites and err on the side of safety.
When ingested in sufficient amounts this oil, eucalyptol, is an irritant to the gastrointestinal system, causing discomfort, vomiting, and diarrhea. ... If your dog has ingested any part of the eucalyptus plant or a product containing eucalyptus oil it is important to contact your veterinarian as soon as possible.<<
There is a saying... we do better as we learn better. I've lucked out on dogs not dying from garlic, grapes, chocolate, onions etc before I knew... but who knows how many times they were sick or distressed and I didn't connect? You can't protect from everything, but at least I try with known issues.