Garlic is a relative of onions. Although not as bad as onions it can cause hemolytic anemia in some dogs if given in appropriate amounts. I tried Garlic in my previous dog, and it had no effect. My Daisy actually liked the taste of the garlic pills. But then again she liked any food.

Some of the constituents of tea tree oil can be absorbed through the skin, and cause neurotoxicity or even seizures in sensitive dogs. Thus if you are going to use over a large area, it should be diluted 1:3. It can be found at your local GNC store. Never heard of it being used for fleas, but it does have some volatile aeromatic compounds that might discourage fleas from hanging around. The only time I've used tea tree oil and at full strength was as a film covering over ointment to discourage licking of a wound. It will sting raw skin if placed direct, so if it hits flea bites that are infected...

The program pill which sterilizes the female flea's eggs works wonders. The Sentinel for heartworm medication has the program incorporated into it. Program is what won the battle of the fleas in my prior dog. My current two do not seem bothered with fleas courtesy of Sentinel.

I have mine on Frontline for ticks, but I find it fustrating to apply, making sure it gets into the skin. Also I wonder if it really is that effective against ticks? They are horrible this year in NC. Then there is the worry about future side effects.

Do not use the commercially available flea powders. Most if not all have carbamyl compounds which are known carcinogens.