What do I do about my mother?

Shes got facebook and talks to men all the time. She is always ringing, texting and meeting them. I think in my area she is starting to get the reputation as a slag as every time people see her she is with somebody different! She is always talking about kissing men when she is on the phone to her friends and she is not discreet about it at all. I'm starting to lose respect for her. She has had a tough life but she goes through phases with men but now it is at an all time high! She doesn't introduce them to us (well not often). She doesn't drink, smoke or take drugs (not even medicated) but when it comes to men... Its like they are her drug :S. Sometimes I try to talk to her but she just guilt trips me or ignores me!...?