Though there is no medical research that solidifies these claims but the available information online definitely supports it. It is a traditional Indian remedy that involves swishing oil in the mouth that improves oral health and treats various ailments.
Interesting question. I have no personal experience with it but my brother had asked me about it also. I did a little preliminary research on it with some academic research articles and found several articles stating that it does seem to help. But these articles were all done by the same researcher and it was done in India where its more commonly done. As far as I can tell, it can show some promise but I wouldn't say it definitely works.