Brewing giant SAB Miller said lager sales fell by 5% in Europe in the six months to September.
The company, whose brands include Miller Lite, Peroni and Grolsch, picked out Poland, the Czech Republic and Romania for particularly poor sales.
Weak economies in the region and changes in taxes on alcohol contributed to the slide.
That was offset by strong growth elsewhere and, overall, lager sales rose by 1%.
Africa was particularly strong, with sales of lager across the continent increasing by 11%.
The best-performing countries included Uganda, where sales rose by 23% thanks to extra brewery capacity, and Zambia, up by 15% because of a cut in excise duty.
In South Africa, lager sales grew by 3%.
The group added that its soft drinks sales were up 2% in the period.