I would be careful with the flea drops. Shortly after we first found our cat (she was a stray), we put a chemically treated flea collar on her. It was meant to keep the whole of her free of fleas. It only needed to be replaced every few months so it should have been a convenient solution. Since we had a dog already (and later found another), it did seem possible that we would end up with fleas in the house. In fact, none of our dogs ever had fleas despite frequent contact with other dogs and walks in many local parks. Perhaps the local climate was not conducive to the life cycle of the flea. Certainly, it was not the result of any particularly conscious effort on our part. Anyway, the collar we put on the cat gave her a terrible chemical burn. It was so severe that some of her coat never grew back again. It was not immediately visible after a while because the hair around it covered it up. However, there was always a patch on her neck, which stayed bald permanently. This happened before I was born so I do not know whether it caused her any discomfort. I imagine it cannot have been pleasant for her though.