While dogs can eat some of the same foods that we do, there are many they should not eat. Some common foods you may have around your house could kill your dog in the right amount.

Some foods dogs should not eat

If your dog has ingested any of these foods, get veterinary help immediately
Grapes and Raisins: Grapes and raisins can cause kidney failure in dogs. As little as a single serving of raisins can kill a dog
Onions: Onions destroy red blood cells and can cause anemia.
Chocolate: Chocolate can cause seizures, coma and death. Baker’s chocolate is the most dangerous. A dog can consume milk chocolate and appear to be fine because it is not as concentrated, but it is still dangerous.
Coffee, Coffee grounds, tea and tea bags: Drinks/foods containing caffeine cause many of the same symptoms chocolate causes
Macadamia Nuts: Macadamia nuts can cause weakness, muscle tremor and paralysis.
Animal fat and fried foods: Excessive fat can cause pancreatitis.
Bones: Bones can splinter and damage a dog’s internal organs.
Tomatoes: Tomatoes can cause tremors and heart arrhythmias. Tomato plants and the most toxic, but tomatoes themselves are also unsafe.
Avocados: The fruit, pit and plant are all toxic. They can cause difficulty breathing and fluid accumulation in the chest, abdomen and heart
Nutmeg: Nutmeg can cause tremors, seizures and death
Apples, Cherries, Peaches and similar fruit: The seeds of these fruits contain cyanide, which is poisonous to dogs as well as humans. Unlike humans, dogs do not know to stop eating at the core/pit and easily ingest them.
Raw eggs: Raw eggs can cause salmonella poisoning in dogs. Dogs have a shorter digestive tract than humans and are not as likely to suffer from food poisoning, but it is still possible.
Salt: Excessive salt intake can cause kidney problems.

Food that most dogs can eat:
Some “human” foods are good for dogs. Most of these are healthier than the boxed treats you buy in the grocery store. . This is just a small list of examples of foods dogs can eat, not a list of every food they should eat. Dogs won’t necessarily get all the nutrients they need if they eat these foods exclusively, so check with your veterinarian if you are interested in feeding your dog a home cooked diet.
Any food that causes stomach upsets or digestive problems in your dogs should be avoided. Like people, some dogs cannot tolerate certain foods

Meats:
Meats should be boneless and it’s best if the skin is removed. I don’t consider raw meat a good idea because of the small risk of food poisoning and parasites.
Skinless, boneless chicken breast
Skinless, boneless turkey breast
Boneless fish

Vegetables:
Dogs have shorter digestive tracts than humans and cannot digest most vegetables whole or in large chunks. It’s best to put them through a food processor before giving them to your dog
Carrots
Green Beans
Lettuce
Potatoes
Yams

Grains:
Grains should not be given in large amounts or make up a large part of a dog’s diet, but these foods are generally safe in small amounts
Rice
Bread

Dairy products
Use caution with dairy products as they are high in fat and can cause pancreatitis, gas and diarrhea. Usually, nonfat plain yogurt is safe in small amounts weekly. 

Source : http://www.wikihow.com/Avoid-Foods-Dangerous-for-Your-Dog

How to Avoid Foods Dangerous for Your Dog

There are some common foods on the human table that are deadly for dogs. It is important to know about them to avoid causing severe or fatal illness in your loyal canine companion.
Understand that even though you can eat the food, this does not mean that your dog can eat it also.
Familiarize yourself with the top human food culprits:

Chocolate contains theobromine (a methylxanthine derivative). It can cause a dog to vomit, have diarrhea, pant excessively, urinate frequently, develop a great thirst, have seizures, show hyperactivity, get an abnormal heart beat and possibly die. The negative effects depend on the dosage, the size of the dog, and the type of chocolate.[1]

Caffeine/Coffee warrant the same precautions as for chocolate. Caffeine, like theobromine, is a methylxanthine derivative with similar effects on dogs.

Alcohol can cause vomiting, diarrhea, lack of coordination, poor breathing, abnormal blood acidity, coma and death, just like in humans. The difference is that dogs are much smaller and are more susceptible to intoxication.

Onions, garlic and chives in all forms (dry, raw, cooked) contain thiosulphate, which can irritate the gastrointestinal system of your dog. A relatively high dosage (600-800 grams) in one meal or spread apart over a few days can damage red blood cells (haemolytic anaemia)[2].

Macadamia Nuts (both raw and roasted, as well as macademia butter) contain an unknown toxin that causes cause locomotory difficulties: weakness, panting, tremors and swollen limbs. [3]. Commonly in cookies, so be careful what you feed your dog.

Grapes and Raisins - can lead to kidney failure [4]. As yet, it is not known what substance in grapes causes this. Be careful, as raisins are often in cake and cookies.

Avocado - the substance Persin can cause vomiting, diarrhea and sometimes heart congestion.

Yeast dough - this refers to the dough prior to cooking. The yeast can continue to rise in the dog's stomach and cause painful bloating, gas and even rupture of the intestines or stomach.

Raw or undercooked meat and eggs - as with humans, care needs to be taken in handling raw meat and eggs to avoid the possibility of contamination with Salmonella bacteria and E. coli. Raw eggs contain an enzyme (avidin) that can lead to skin and coat problems for a dog.

Milk - owing to the lack of lactase, consumption may lead to bloating, gas, diarrhea and other digestive upsets.
Xylitol - this can lead to liver failure through the over-release of insulin, vomiting, lethargy and loss of coordination. It does not take long to see signs of nearing liver failure - only a few days. Be very careful as this substance in a wide range of products, such as candy, chewing gum, toothpaste and baked goods.

Bones can cause choking, or they can break apart into jagged pieces that become lodged in the digestive tract. Look for sturdy marrow bones that are less likely to splinter or nylon bones that wear down slowly.

Check the food you are sharing carefully. Many of these ingredients are tucked away in cookies, bread, cake, preserves and other processed foods. It is really important to be aware of what you are feeding your canine companion so that you can avoid these problem foods.
Ensure that your dog eats a healthy and balanced diet. Read up on the appropriate foods for your dog type and make regular vet visits to ensure that your dog is in top shape.
Minimize snacks from the human table. It encourages poor manners from both the dog and the human and it blurs the line between what is good food for the animal and what is not. Start out right and keep it right.
Contact your vet immediately if you see any signs of weakness, poisoning, lack of coordination, lethargy, frothing or any other unusual behavior after consuming any of these foods. Delay can be fatal so do not hesitate.

Tips - Cooked bread is okay in very small amounts.
Show children this list and teach them early what they can and cannot feed their dog(s).

Warnings - Take your dog to the vet immediately if it shows any signs of poisoning or any of the symptoms described above following consumption of any of these foods.
Be aware that just because you may have fed the dog once on a bad food that this does not mean the dog can consume it. Some foods have a cumulative effect and the dosage can be key to whether or not there is a fatal or severe reaction.
Always place table scraps and other garbage in a secure container, where the dog can't get to it.
Never allow your dog to eat food or treats he finds on the ground in public.