I would never give my dogs a oral pill for fleas. Nope, nope, nope.

We have been giving both of our jack russels Confortis for 2 years now and they have had no ill effects. It keeps the fleas off. Maybe the dogs who become ill are just allergic to something in the pill. Our dogs are outside most of the day and also enjoy one day a week at the dog daycare, Tails are waggin, and never come home
with an infestation. No fleas in our carpet either. If they work and your dog suffers no ill effects, good. If they have problems with it then don't give it to them. We cannot use the sprays as one of our jacks gets a terrible skin rash. We will continue to use Confortis.