Yes, so keep that glass of beer, wine or your choice of alcohol away, if you want your immune system to stay in top-notch shape. While a glass of alcohol here and there may not do much harm, it is the excessive consumption of alcohol which heavily impacts your immune system. Infact, several studies have noted the link between excessive alcohol intake and weakened immunity. Both binge drinking and excessive drinking may leave you more susceptible to pneumonia and other respiratory illness as well. Hence, one should stick to one drink a day for women and no more than two drinks a day for men.