Small amounts of alcohol can actually be beneficial to health. Large quantities, especially on a regular basis, can have serious harmful effects. The recommended safe limit is 17 units a week for men and 11 units for women. A unit being approximately – half a pint of beer, a glass of wine, or a single measure of spirit. This accepted maximum presumes that the consumption is spread throughout the week and not consumed all at once in a ‘binge’.
Links: http://www.drinkaware.ie