What Causes Sudden Nausea And Vomiting?

My wife is a healthy white female of scottish cherokee background. She is 5-4, 145 lbs. Non-smoker, social drinker. She has suffered from anxiety issues but is not medicated for them. She has never suffered from any issues after having a few drinks. In the past 6 months, she has curtailed most of her social drinking because of episodes of vomiting hours after. Today, she had breakfast and coffee with me at Starbucks at 0930. We met her dad for lunch (1300) and she had a slice of peperoni pizza, a salad and two 12oz beers, We later went shopping for a few hours and had an iced coffee before returning home. We watched a tv movie till about 1730. At 1730, she became suddenly very nauseous and began vomitting. She experienced a single epsiode and another about 15 minutes later. This scenario has occurred several times in the past 6 months but never with so modest an amount. There is obviously something going on we don t know about and thought we d start with an opinion on your site. Please direct us.