Makes you fat and turns your shit black... and prevents heart attacks!

Research has shown that 24oz of Guinness a day may be as effective as aspirin at preventing arterial blood clots.

On a side note, I just learned that Guinness and a lot of other beers are not technically vegetarian (and will likely kill delicate vegans). A commonly used clarifier in beer and wines is isinglass, obtained from fish swimbladders. Plus there's gelatin in a lot of wine, etc etc.