While some of these on the list can harm dogs directly, others will build up toxins over time. Best bet is to avoid all on this list.
1. Alcohol
Causes weakness, vomiting, dangerously low blood pressure, coma and death in pets.
2. Apple, Apricot, Cherry and Plum Seeds/Pits
These pits contain cyanide which can cause vomiting, irregular and fast heartbeat, seizures, coma and death due to the inability of red blood cells to properly carry oxygen to cells.
3. Avocado
Contains persin, a toxic compound that causes vomiting and diarrhea.
4. Broccoli
Contains isothiocyanate which can be harmful to pets in very large doses.
5. Caffeine
Contains methylxanthines which can cause potentially fatal diarrhea, vomiting, seizures and irregular heart beats.
6. Chives
Can cause potentially fatal anemia in dogs (and cats).
7. Chocolate
Contains methylxanthines which can cause potentially fatal diarrhea, vomiting, seizures and irregular heart beats.
8. Garlic
Can cause potentially fatal anemia in dogs (and cats).
9. Grapes and Raisins
Can cause severe and potentially fatal kidney failure.
10. Ham
May cause pancreatitis, a potentially fatal disease, due to high fat content.
11. Macadamia Nuts
Contains an unidentified toxin that can cause vomiting, weakness, joint pain and inflammation.
12. Milk & Dairy Products
May cause diarrhea and gas in adult animals who are lactose intolerant.
13. Mushrooms
Many types contain many different toxins that may cause kidney and liver failure, vomiting, diarrhea, hallucination and damage to red blood cells.
14. Nutmeg
May cause hallucinations and severe vomiting.
15. Onions
Causes potentially fatal oxidation of red blood cells leading to their destruction and causing anemia.
16. Salt
Excessive amounts of salt can cause a change in the fluid balance of cells thus causing tremors, seizures and coma (this includes rock salt and homemade playdough).
17. Spicy Food
Extra heat added to a dish could potentially cause vomiting, stomach ulcers or diarrhea.
18. Sugar-Free Gum & Candy (Xylitol)
Causes a potentially fatal drop in blood glucose (blood sugar) followed by severe liver damage.
19. Tobacco
Nicotine containing products can cause excitement, vomiting and tremors that are usually followed by fatal paralysis.
20. Yeast Dough
Yeast in the raw dough can cause an excess buildup of gas in a pet’s stomach causing severe pain and potential life threatening torsion or rupture of the stomach.
Info from https://www.caninejournal.com