Foods to avoid

Chocolate
Chocolate contains theobromine, a compound that acts as a cardiac stimulant and diuretic.
When affected by an overdose of chocolate, a dog can become excited and hyperactive. Due to the diuretic effect, it may pass large volumes of urine and it will be unusually thirsty. Vomiting and diarrhoea are also common. The effect of theobromine on the heart is the most dangerous effect. Theobromine will either increase the dog’s heart rate or may cause the heart to beat irregularly. Death is quite possible, especially with exercise.
After their pet has eaten a large quantity of chocolate, many pet owners assume their pet is unaffected. However, the signs of sickness may not be seen for several hours, with death following within twenty-four hours.
Cocoa powder and cooking chocolate are the most toxic forms. A 10-kilogram dog can be seriously affected if it eats a quarter of a 250gm packet of cocoa powder or half of a 250gm block of cooking chocolate. These forms of chocolate contain ten times more theobromine than milk chocolate. Thus, a chocolate mud cake could be a real health risk for a small dog. Even licking a substantial part of the chocolate icing from a cake can make a dog unwell.
Semi-sweet chocolate and dark chocolate are the next most dangerous forms, with milk chocolate being the least dangerous. A dog needs to eat more than a 250gm block of milk chocolate to be affected. Obviously, the smaller the dog, the less it needs to eat.

Raisins & Grapes
This is a fairly new addition to the dangerous foods list, but is very dangerous and potentially lethal.
As few as 2 raisins can make a 10lb dog very ill. Symptoms include vomiting, abdominal pain, breathing difficulties, renal failure and death.

Onions & Garlic
Onions & garlic contain the toxic substance Thiosulphate. Onions are more of a danger than garlic, which is commonly given safely in small amounts to dogs.
Pets affected by onion toxicity will develop haemolytic anaemia, where the pet’s red blood cells burst while circulating in its body.
At first, pets affected by onion poisoning show gastroenteritis with vomiting and diarrhoea. They will show no interest in food and will be dull and weak. The red pigment from the burst blood cells appears in an affected animal’s urine and it becomes breathless. The breathlessness occurs because the red blood cells that carry oxygen through the body are reduced in number.
The poisoning occurs a few days after the pet has eaten the onion. All forms of onion can be a problem including dehydrated onions, raw onions, cooked onions and table scraps containing cooked onions and/or garlic. Left over pizza, Chinese dishes and commercial baby food containing onion, sometimes fed as a supplement to young pets, can cause illness.
Onion poisoning can occur with a single ingestion of large quantities or with repeated meals containing small amounts of onion. A single meal of 600 to 800 grams of raw onion can be dangerous whereas a ten-kilogram dog, fed 150 grams of onion for several days, is also likely to develop anaemia. The condition improves once the dog is prevented from eating any further onion
While garlic also contains the toxic ingredient thiosulphate, it seems that garlic is less toxic and large amounts would need to be eaten to cause illness.

Macadamia Nuts
The toxic compound is unknown but the affect of macadamia nuts is to cause locomotory difficulties. Dogs develop a tremor of the skeletal muscles, and weakness or paralysis of the hindquarters. Affected dogs are often unable to rise and are distressed, usually panting. Some affected dogs have swollen limbs and show pain when the limbs are manipulated. This can occur in all breeds of dog with as few as 6 macadamia kernels (nuts without shells)

Fruit Pips & Kernels
The pips of apples & pears, and the kernels of peaches, apricots and plums, contain cyanotic gluycerides - which can lead to cyanide poisoning.

White Potato
Potato peelings and any raw green part of a potato are potentially dangerous, due to solanium alkaloids which is the compund of the nightshade plant family. Sweet potatoes and cooked potatoes are safe, and raw potato as long as ALL green parts and sprouts have been removed.

Other Hazards
Rhubarb Leaves
Tomato stems & leaves
Yeast dough
Hops
Coffee grounds/beans
Tea leaves
Cigarettes/Tobacco
Broccoli - in very large amounts

I have read plenty about garlic being toxic, I never use it on any of my dogs,
but have you noticed how many dog remedys contain garlic

I know a group of people who use garlic as a homeopathic remedy for worms, and have done for years fed daily??

I didn't know garlic was toxic - I've seen doggy recipies on the web before and they contain garlic - aparently dogs love it?

I know its odd but thats the recommendations from the vets, I am sure that most dogs would be fine but personally would not be happy to take the risk with it in food form. I am sure the tiny amount in tablet form would be fine.