re: Can a flea collar make a dog sick by just wearing it

I use the drops that you put between the shoulders once a month, and the Natural Care spray that you can spray on you dog, and bedding and stuff. Seems to work well so far, I've only had my dog for 3 wks but when I took him in for his shots, I noticed none of the dogs had flea collars. I don't think many people use them anymore.