Avocado – never give this to your dog as it contains a chemical called Persin which is very toxic to most animals, causing vomiting and diarrhea.
Alcohol – Any alcohol or foods containing alcohol because alcohol has the same effect on a dog's liver and brain that it has on humans. But it takes far less to do its damage. Just a little can cause vomiting, diarrhea, central nervous system depression, problems with coordination, difficulty breathing, coma, even death. And, the smaller the dog, the greater the effect.
Onions - Onion in all forms - powdered, raw, cooked, or dehydrated - can destroy a dog's red blood cells, leading to anemia. An occasional small dose is probably safe but I stress the word OCCASSIONAL. But just eating a large quantity once or eating smaller amounts regularly can cause onion poisoning. Symptoms include vomiting, diarrhea, little interest in food, dullness, and breathlessness.
Caffeine - Caffeine in large enough quantities can be fatal for a dog. And, there is no antidote. Symptoms of caffeine poisoning include restlessness, rapid breathing, heart palpitations, muscle tremors, fits, and bleeding. In addition to tea and coffee - including beans and grounds - caffeine can be found in cocoa, chocolate, colas, and stimulant drinks such as Red Bull. It's also in some cold medicines and pain killers.
Grapes and Raisins - Although it isn't clear why, grapes and raisins can cause kidney failure in dogs. And, just a small amount can make a dog ill. Repeated vomiting and being hyperactive are early signs. Within a day, the dog will become lethargic and depressed.
Milk and dairy products – milk and other dairy products can cause diarrhea and other digestive upsets and also set up food allergies which might manifest in itchy skin.
Nuts – Nuts can be lethal to your dog. As few as 6 macadamia nuts can be fatal to your dog causing illness, muscle tremors, weakness or paralysis of hindquarters, elevated tempreture, rapid breathing and possible kidney failure and death.
Chocolate - The toxic agent in chocolate is theobromine. It's in all kinds of chocolate, even white chocolate. The most dangerous kinds, though, are dark chocolate and unsweetened baking chocolate. It can also cause abnormal heart rhythm, tremors, seizures, and death.
Persimmons, Peaches and Plums - The problem with these fruits is the seeds or pits.The seeds from persimmons can cause inflammation of the small intestine in dogs.peach and plum pits contain cyanide, which is poisonous to both humans and dogs
Raw Eggs - There are two problems with giving your dog raw eggs. The first is the possibility of food poisoning from bacteria like Salmonella or E. coli. The second is that an enzyme in raw eggs interferes with the absorption of a particular B vitamin. This can cause skin problems as well as problems with your dog's coat.
Raw meat and fish - Raw meat and raw fish, like raw eggs, can contain bacteria that causes food poisoning. In addition, certain kinds of fish such as salmon, trout, shad, or sturgeon can contain a parasite that causes "fish disease." If not treated, the disease can be fatal within 2 weeks. The first signs of illness are vomiting, fever, and big lymph nodes.
Sugar and sugary things – can lead to obesity, diabetes and dental problems.
Salt – TOO MUCH salt can be bad causing the dog to drink large amounts of water and urinate frequently and lead to sodium ion poisoning.
