No, I haven't. But my friend in New Orleans did try Advantix or Advantage (I'm not sure which) for fleas and his Chihuahua was infested with them. It's just that I hear all this horrow stories about dogs having horrible reactionst to flea and tick meds and my dog never got a reaction to Frontline so I stuck with it. I jjust didn't want to risk anything else if this one was working. Well, apparently it's not working since it's a second time tick got one of my dogs while on Frontline... In all fairness, I must say, last summer when Xena got bit, she didn't get sick. This time, it just happened yesterday, so I don't know if we are out of the woods yet, but Beasley seems ok today. So, maybe it is working? No?