I used to give my dogs Brewers Yeast tablets with Garlic and 2 of the dogs ended up with anemia. The one dog passed away from it and the other dog was lucky enough to survive through it.
As far as my experience with giving dogs garlic, I would NEVER reccomend that anyone give their dogs garlic. The vet that owns the animal hospital that I took both of my anemic dogs to said that it was unheard of for someone to have 2 dogs become anemic shortly one right after another. Now I realize that giving the dogs so many garlic pills for fleas daily may have contributed to their medical problem. I have always regretted giving my dogs these pills and wish I knew then what I know now. My one dog may still be alive if I did.
My adult boxer ate two-thirds of a bag of treats made in part with garlic powder that were accidentally left on the counter and ended up in the ER with blood in his lungs and around his heart. He was having trouble breathing and was coughing and spitting up blood. He has runny stools, as well, and is (was - he's getting better) very lethargic. When first in the ER, it was believed his condition was some type of pulmonary edema until they began questioning whether he had gotten into any plant fertilizer, mouse poison, weed killer, garlic, onions. Bingo! Garlic flavored treats with garlic powder. In small doses, ie., one treat a day, two a day I'm sure it's fine, but the several ounces he ate could have killed him. We will from this point forward always check ingredients on all treats we give our dog to ensure garlic/onion and associated powders are not included. It concerns me that online I'm reading that so many people give their dogs garlic and companies sell products that contain garlic. We won't take that chance again.
Owosso, Michigan, USA
Montesano, Wa. Usa
garlic is in the onion family and onions are toxic to dogs. they can cause hemolytic anemia (basically kills red blood cells). my dog had hemolytic anemia and it is no joke! a blood tranfusion and thousands of dollars in vet bills to get her better. she is a shih-tzu mix and I have heard shih-tzus are especially predisposed to h.a.
Summerland, Bc, Canada
Recent research sets the LD50 (lethal dose at which 50% of subjects die) of garlic in dogs at approximately 5 grams per Kg.
So the dog who got sick from eating a whole bulb of garlic may have gotten a dangerous amount if the bulb was 50 grams like the ones I buy and the dog was 10 kg or so (22 lbs). Smart per owners will keep all medicines, natural or not, in a safe storage.
That being said, much valid research seems to indicate nothing but good effects from a clove of garlic a day for dogs (use Google Scholar to search for and see all the papers on the web). For tiny dogs a tiny piece is likely all that is needed.
My Thai Dog puppy loves garlic, but as he only weighs 12 Kg at 5 months old, one clove a day is all he gets. The vet says he looks great and tests show no intestinal worms.
I have given garlic to all my dogs and they never have fleas or worms, and live long healthy lives. One Golden Retriever in particular was a real pig and would raid the shopping bags while you were getting the rest in. At one time he consumed 2 loaves of bread in a couple of gulps, another time a pound of sugar! Not to mention a lot of unspeakable stuff he would find in the fields. He had no ill efects and he lived to 17. Dogs usually have pretty strong stomachs! I do feel vets and feed manufacturers have a vested interest in bad mouthing anything natural. Our stable cats never have jabs or wormers and live to ripe old ages. They scrap and get a scratch or an absyss, but this disappears in a day or two on it's own, without sixty quids worth of antibiotics!
hey my dad has been sprinkling garlic powder on his dogs food for about 16 yrs now. He used just enough to cover the top of food shake it into dry food or mix into canned.
About the garlic being harmful, I fed my dog garlic for 20 years. She lived to be 21 yrs old. I also give it to the dogs I have now. Anything, anything is lethal in large amounts, you can even o.d. on water if you drink to much. Onions are considered lethal because of the chemical in it that makes humans sleepy, thats why onions can kill a dog, but not garlic. Like I said, my dog lived to be 21yrs old. She never had any problems.
I have done some searching online to find the pros and cons of Garlic and pets. I have come across a few links that suggest that Garlic can be fatal to pets - see below;
Garlic is part of the onion family (alliaceae) along with leeks and shallots. There is ample research available which indicates onions can be harmful, if not deadly, to our pets. In the last five years, more and more toxicity studies are being conducted on garlic and all seem to indicate that it, too, can pose serious health risks when fed to cats and dogs. A 2003 study on Grape and Raisin Toxicity in Dogs, published in the Australian Veterinary Journal begins, "The list of commonly available human foods toxic to dogs continues to grow. Grapes and raisins can be added to onions, garlic, chocolate, and macadamia nuts as posing dangers when ingested in excessive quantities."  Unfortunately, no one knows what constitutes "excessive quantities".
In an article on Onion and Garlic Toxicity in Dogs and Cats, Jennifer Prince, DVM states: "Garlic and onion are used as flavor enhancers in food. Since the toxic amount is unknown, it is recommended not to add it to your pet's food. These ingredients can cause Heinz body anemia, resulting in a breakdown of the red blood cells and anemia." 
Although the exact toxic dose is not known, studies unanimously agree that foods containing garlic should not be fed to dogs.
Full report available here -
I hate to disagree with anyone about a flea remedy that works for them, but I feel I must say something about the people who support garlic as a cure. I found out the hard way that garlic can severly injure and even kill dogs. Our dog, Chewie, got a hold of a garlic builb and managed to eat most of it before my husband caught him. We didn't think anything of it, he gets into things all the time, but not even an hour later he started vomiting and shaking. He couldn't hold anything down, not even water. It was too late to take him to the vet at that point, so we had to wait untl morning. When we did him to the vet, the vet was just as confused as we were until we told him about the garlic. Then he said, "Oh, that's it."
He explained that certain plants, like garlic and onion, are actually lethal in certain doses. We were lucky because Chewie vomited so soon after eating it. If he hadn't he could gone into renal failure and died.
I don't want to sound like a spoiler for all those who support giving garlic as a flea remedy, but I just don't want someone to loose their pet by giving their dog too much.
I was born in Europe and we always use to give garlic to dogs when they had worms. I have never ever witnessed anything but good results. It worked every time, most times within 24 hours some other times it would take a few days. The dogs lived very long lives, over 20 years of age. when I came to USA I noticed that a dog's life expectancy is more around 15 years and even less depending on the breeds. That is very sad. Now since National Geographic announced that garlic is bad it seems that everyone is ready to throw away hundreds of years of experience. Garlic cannot become bad from one day to an other. I personnaly don't know what I would do without these natural remedies that have worked for ever. I have yet never seen myself a dog who had adverse effect from garlic but I did see many dogs who went into epilepsy after receiving a conventional deworming :( I wish everyone would do more research before jumping to conclusions and believing everything. Sometimes what we hear is just half the truth... and of cousre we are missing the most important half, so we should look for it. The industry has done a spectacular job until now making us believe that what is natural is bad, synthetic is better, fresh real food is bad (they call it human food to make sure you lost your argument before even arguing it), pet food made from scraps(of "human food"), fillers and preservatives is better. Mentionning garlic among other bad foods for dogs does not make the fact that garlic is dangerous more true but it is more convincing.
My 86 lb golden lab chow cross is almost 13 yrs old. Since he was a year old I have been making his dog food - boiled chicken, rice & raw chopped veggies (carrots, zuccini, bell pepper) - I sprinkle dried herbs (basil, rosemary, oregano) & garlic powder into chicken boil. Vets always comment on how healthy my dog is for his age and how nice his teeth are. He is slowing down now but to me it is obvious that the garlic has not harmed him in any way. And I always have lovely chicken broth for myself!
I do agree with Cheryl about the things on her list or (National Geographic magazine list). Except for the garlic. For a dog to become anemia by using garlic it would have to have an enormous amount of garlic. In the of Animal Wellness magazine February 2008 issue, is an article on the benefits of feeding garlic http://www.Animalwellnessmagazine.comrnrnAnother good article is http://www.petstyle.com/dog/health_well_article.aspx?id=2030§ion=Feeding amp Nutrition
I have two dogs 8 & 9yrs old; both get a clove of garlic daily. Small clove mix in raw meat for my little dog 25lbs and on or two cloves mixed in raw meat for my big dogs 60lbs, during the tick season, usually May thru July, Aug. When the tick season ends, I don't give it to them. I have had no side affect or problems with fleas & ticks. At first I had concerns about feeding garlic, after doing much research and reading different forums. I feel very confident garlic is safe to give my dogs. Dogs, like people, are different and each one has a different chemistry. What works well for one may not work for another? It's always best to do the research and use good common since, there's pros and cons for everything. You have to feel comfortable with your choices. But for me, garlic is the best tick repel I can use; I feel it's safe and has no harmful side effects.
I've been giving my small and large dogs fresh garlic cloves, twice a week, for the past 30 years, and they all lived long healthy lives. I used to eat a clove daily and I never got a cold or flu. I gave up the daily garlic because it made me stink. Once I gave it up I began to catch virus. I now only take it if I feel as though I may be coming down with something.
Garlic is perfectly fine for dogs. It does Not break down their blood cells. Onions do though. You will know if they have had onions because they will pee red. With garlic they will not.
YEA. My 3 years old yorkie gets some garlic for almost 2 years once or twice a weak, he gets no fleas or worms. He is on raw food. And with this food and some garlic he is doing well.