I have never used a citronella collar on my Otis because barking is simply not an issue with him, however, I have friends with a ShizTzu/Lhasa Apso mix who barks in certain situations. He does it as "begging" at the table and also when they meet other dogs out walking. We're talking freak-out barking here, not just a couple of yips. Anyhow, it's been really effective in their situation and they usually just have to show him the collar to curb the barking. He doesn't wear it much at all, only if they can predict that there will be a problem and they take it off as soon as he calms down. In any case, it's worked really well for them. I don't think it would be very effective, however, if there was another dog who might bark and set it off accidentally or if you made him wear it "too much". He has tried the barking just loudly enough to not set it off as well but if you can still carry on a conversation over dinner, it's definitely an improvement!!