to hate my mother when she drinks

[sickovit]

Most people are happy when they have had a few drinks, or they become mellow and relaxed, what I would call 'happy drunks' (if there is such a thing)
But my mum is the complete opposite. Sober, she isn't too bad and is an interesting person to talk to. But as soon as she has had more than one glass of wine her personality changes completely and she becomes very Opinionated, Loud and Nasty.
Recently we all went out to celebrate a family Engagement. Within the hour she had finished one bottle of wine and was on the second. Her personality flipped completely, to the extend that she was arguing and hurling barbed insults at most people round the table, over the pettiest of things! (I think she thinks she is being interesting)
People were trying to ignore her but it was very difficult. One of the couples left early and I'm sure it was down to her.
I now feel very wary of going to any more family celebrations.
It's the nasty aggresiveness that bothers me the most.

What would you do? Should I talk to her? Does she have a drink problem?
One other bit of information, she is looking very bloated lately, so could she be a secret drinker?

Same problem here but my Mother in law. Have had years of trouble at family occasions with her getting out of hand and uncontrollable. She is now kept away from most gatherings so they are not ruined and, as she gets older, this becomes easier. We have to do this as she's a loud woman, especially if the venue is outside the family home.
If we really have to have her attend anything we give her two strong drinks at the start so she's off guard and then refill constantly with drinks that are very watered down, in huge glasses, so she thinks she is getting a good deal. It really works. Make sure her favourite food is offered to soak it all up. Plus she spends all night running to the loo and ends up exhausted!