First let’s look at the steps necessary to keep the fleas away; without using chemicals. This natural flea prevention will work best to prevent fleas from taking hold and can also be used if you have a very light flea infestation.
Keep your carpets vacuumed! Vacuum daily and get some wide tape to seal up the vacuum bags as soon as you remove them from the vacuum cleaner. If you DON'T have small children around, use pennyroyal leaves either fresh (if available) or dried and spread them around your carpet to repel fleas.
Keep your dog's bedding clean by washing it in warm water and soap. When it is dry apply some cedar oil to the bedding to help repel the fleas. Keep the area around your dog's bed free of dust and dirt.
Give your dog a bath once a week with cedar shampoo (bathing more frequently may dry out its skin). If your dog does get dry skin it will attract fleas -- just what you don't want. Give a dog with dry skin some Linatone oil mixed with its food. Something else you can mix, in very small doses, with your dogs food to repel fleas is a mixture of garlic and brewer's yeast. With this mixture in the dog's system, it will give off a scent that you won't be able to notice but fleas will notice it and they hate it.
If you mix lavender oil (60 ml) with rock salt (2.8 liters) you will have a great flea repellent that can be spread around the places where your dog goes and can also be used as a dog shampoo.
Fill your outside flower beds with marigolds -- they have natural flea repellent properties and also repel other bugs.
Try boiling either lemon peels or orange peels in water to create a solution that can be used as a dog dip and can be used on the dogs bedding before washing it.
Another effective dog dip, if you are experiencing a light infestation, is warm water, shampoo and laundry detergent; immerse the dog’s body in this for ten or fifteen minutes and then rinse thoroughly.
If you have a heavy flea infestation you may have to resort to chemicals -- all these products can be used safely if you follow the directions that come with the products.
Advantage. Advantage is a flea poison made by Bayer. Apply the Advantage (liquid) to the dog's coat as directed. Advantage should work for about one month, Advantage's active ingredient, imidacloprid, upsets the nervous system of any flea that comes in contact with it. Advantage kills flea's fast and should kill all the fleas on the dog in about two days; but it is not absorbed into the dog's bloodstream or internal organs. The active ingredient, imidacloprid is a chloronicotinyl nitroguanidine, integrated from the nitromethylene class of a compound. The imidacloprid affects the nicotinyl receptor sites of insects and upsets the flea's normal nerve transmission, resulting in death. Advantage costs $15 to $20 for a set of two vials.
Frontline. Frontline is very similar to Advantage but it is not water soluble; this means alcohol is required to wash it off the dog. Frontline is safe for use on puppies as well as adult dogs, kittens and adult cats and it will work for approximately four months.
The active ingredients in Frontline include: Fipronil 5-amino -1- (2, 6-dichloro-4 [trifluoromethyl]phenyl) -4- (1,R,S)- (trifluoromethyl0sulfinyl) -1H-pryazole-3-carbonitrile 0.29% inert ingredients 99.71%. Fipronil, from the new phenylpyrazole class, is very effective at killing fleas by attacking their nervous systems. Fipronil is safe for use on dogs and cats that are not allergic to it. Tests have shown that Fipronil will kill up to 95% of a pet's fleas within two hours and all the fleas within the first 24 hours -- ticks are killed instantly on contact.
Knockout. Knockout is as effective as Frontline and works in the same way but Knockout can not be used on cats.
Knockout's active ingredients are: Pyriproxyfen: 21[1-methyl-2-(phenoxyphenoxy)ethyoxy] pyridine....0.05% cyclopropanecarboxylate 2.00% inert ingredients 97.95% Knockout also contains NYLAR, a flea-growth regulator.
Biospot. Biospot is used topically, like the other products and, in tests, killed up to three quarters of the fleas, ticks and their eggs; like Knockout, Biospot can NOT be safely used on cats. Biospot works for about one month and can also be used as a mosquito repellant. Biospot has been known to temporarily turn the white hair on a dogs coat to yellow.
Biospot contains permethrins and IGR.
Proban and Prospot. The Proban (cythioate) and Prospot (Fenthion) products are also for use on dogs only and they are very popular. Proban and Prospot are actually absorbed in the dog’s bloodstream, poisoning any fleas that bite the dog. The fact that these products are poisonous to fleas combined with the fact that you are actually allowing this poison to be absorbed in the dog's blood stream, may be cause for concern. There are no published (or known?) side effects. Another factor to consider about these last two products is that they do not repel fleas, they will only work if a flea bites the dog -- if the dog has a flea allergy this would not be the product of choice.