are onions and garlic toxic to Dogs and cats ?

UNfortunately onions and garlic are toxic to dogs and cats thu they are really beneficial to humans but in dogs and cats they destroy the red blood cell resulting in anemia and cells failure in transferring oxygen * leading to many internal organ
failures * and death

and here we are quoting from banfield website :
Toxicity can occur whether the products are fresh, cooked or in a dried/powdered form such as in spices.

Signs of Toxicity :
Lethargy
Weakness
lack of muscle coordination
Pale gums
Red or brown discolored urine
Hyper-salivation
Occasional vomiting and/or diarrhea
 

Treating Toxicity Caused by Garlic and Onions :
If the toxicity is caught early, your veterinarian can induce vomiting and decontaminate your pet’s gastrointestinal system with activated charcoal. Once clinical signs develop, supportive care including IV fluids (to maintain hydration) and oxygen therapy are the main forms of treatment. Some pets may require a blood transfusion.


Other Common Human Foods Considered Poisonous to Pets :

Alcohol – Pets can often get into alcohol through uncommon sources, like unbaked dough or rum-soaked desserts. Alcohol will give your dog or cat low blood sugar and low body temperature. It can end in coma or seizures.

Avocado – Dogs and cats can have poisonous reactions to avocados, but they are most toxic for birds. After eating some of the fruit, birds develop respiratory distress and many die.

Caffeine – Pets will react to caffeine with vomiting, diarrhea, increased thirst, restlessness and increased heart rate. Caffeine is a toxic stimulant to cats and dogs.

Chocolate – Most pet owners recognize that chocolate is very toxic for their dogs or cats. The darker the chocolate, the more dangerous it can be, because it has more caffeine and theobromine.

you can read our detailed article about Chocolate Toxicity on :
http://online-vetclinic.blogspot.com.eg/2015/08/is-chocolate-toxic-to-dogs-cats.html

Grapes and Raisins – Both grapes and raisins can cause acute kidneys failure in dogs and some cats. Owners should keep these out of reach in every form, including raisin bagels or grape juice.

Mushrooms – Not all mushrooms are toxic. However, some can be a gastrointestinal irritant, others can be hallucinogenic for a pet, and some can cause acute liver failure and death.

Sugar-Free Foods (Xylitol) – The natural sugar substitute Xylitol can be very dangerous for dogs. It will cause a drop in blood sugar and potential liver damage.


references :
http://www.banfield.com/pet-health-resources/preventive-care/nutrition/garlic-and-onions-are-poisonous-to-dogs-and-cats