Common sense should tell you that your dog is not a garbage disposal. Just like people, dogs have dietary requirements and certain foods can cause them gastric and other problems and even death. It should be obvious that things like alcoholic beverages, drugs, and the excess fat you trim off your meat should not be fed to your pets.
Alcoholic Beverages - Can cause intoxication, coma, and death.
Almonds and nuts in general.
Anise Oil
Apples - The fruit is safe, the leaves and roots are not.
Avocado
Baby Food - Can contain onion powder, which can be toxic to dogs. Can also result in nutritional deficiencies, if fed in large amounts.
Bones from Fish, Poultry, and Other Meats - Can cause obstruction or laceration of the digestive system.
Brazil Nuts
Broccoli and Liver - Are good for your dog if given in moderation. If given as more then 10% of your pet's diet, it can lead to illness.
Caffeine - Avoid chocolate, coffee, tea and all other caffeine containing products.
Canned Tuna
Carrob Chips
Cat Food - Too high in protein and fats.
Cherries - The fruit is safe, the leaves and roots are not.
Cheese
Chocolate - Affects the heart and nervous system. Can cause heart attack.
Chewing Gum and Candy - If it contains Xylitol, it can lead to seizures and lethargy.
Citrus Oil - Can cause vomiting.
Cocoa Powder
Coffee, Tea (including green tea), and Other Caffeine Drinks - Contain caffeine, theobromine, or theophylline, which can be toxic and affect the heart and nervous systems.
Corn
Cucumber
Cranberries
Dairy Products - Can cause diarrhea. Try lactose-fee milk products. Cottage cheese and yogurt appear to be more stomach friendly.
Deer Meat
Eggs (raw)
Fat trimmings and Turkey skin - Can cause pancreatitis.
Food Coloring
French Fries
Garlic - Contain sulfoxides and disulfides, which can damage red blood cells and cause anemia. Garlic is less toxic than onions.
Grapes - Can cause kidney failure.
Grapeseed Oil
Grease
Hops (as found in beer) - Causes panting, increased heart rate, elevated temperature, seizures, and death.
Lemon Seeds
Luncheon Meat
Macadamia Nuts - Contain a toxin that affects the digestive and nervous systems.
Milk
Mushrooms - Can contain toxins, which may affect multiple systems in the body, cause shock, and result in death.
Nutmeg - Affects Central Nervous System and can lead to seizures and death.
Onions and Garlic - Contain sulfoxides and disulfides, which can damage red blood cells and cause anemia. Garlic is less toxic than onions.
Oranges
Peaches and Plums - The pits can cause obstruction of the digestive system.
People Vitamins with Iron - Can damage the lining of the digestive system and be toxic to the other organs including the liver and kidneys.
Pepper - Can irritate the skin, eyes, nose and gastrointestinal tract .
Persimmons - The seeds can obstruct the intestinal tract.
Popcorn - Will not make them sick, but is a significant choking hazard.
Potato Peelings and Green Potatoes - Affects digestive, nervous, and urinary systems.
Potato Chips and Pretzels
Raisins - Can cause kidney failure.
Raw Eggs - Contain an enzyme called avidin, which decreases the absorption of biotin (a B vitamin). This can lead to skin and hair coat problems. Raw eggs may also contain Salmonella.
Raw Fish - Can result in a thiamine (a B vitamin) deficiency leading to loss of appetite, seizures, and in severe cases, death. More common if raw fish is fed regularly.
Salt - If eaten in large quantities it may lead to electrolyte imbalances.
Spices - Italian and curly parsley and coriander are considered to be non-toxic and edible, but may cause stomach irritation. Garlic, mace, paprika and turmeric should be avoided completely.
Spinach
Steak Fat
Sugar and Sweeteners - Can lead to obesity, dental problems, and possibly diabetes mellitus.
Table Scraps
Tobacco - Contains nicotine, which affects the digestive and nervous systems. Can result in rapid heart beat, collapse, coma, and death.
Tomatos - Ripe tomatos are not toxic, however the green parts of the tomato plant are considered toxic.
Walnuts - Can cause gastroenteritis.
Water (filtered)
Watermelon
Wine
Yeast Dough - Can cause rupturing of the stomach and intestines
Yogurt
Zucchini