“…many of these reports are probably due to an allergic reaction from the dying fleas as opposed to an actual reaction to the product itself.”

What? Where did you get that information? This is completely inaccurate. Permethrin can cause local skin reactions as well as penetrating into the nervous system causing incoordination, stumbling, and seizures. Dying fleas have no effect on the immune system of dogs or cats.

A couple words of wisdom as well: Permethrin and other pyrethroids have become much less effective over time due to developing resistance in fleas, especially in the south. There is also very little residual activity with these products – there is no way they will keep fleas away for a month. With so many safer, MUCH more effective products on the market, why take the risk? Buyer beware: you get what you pay for.

Also: any product containing permethrin is EXTREMELY toxic to cats, and should NEVER be used on a cat or on any dog that a cat is likely to be in close contact with and be grooming.