FRANKFURT—The European Central Bank ushered in a new era by launching an aggressive bond-buying program Thursday, shifting pressure to Europe’s political leaders to restore prosperity in one of the global economy’s biggest trouble spots. (Update:Eurozone consumer prices fall sharply).

Investors cheered the ECB’s commitment to flood the eurozone with more than €1 trillion ($1.16 trillion) in newly created money, sparking a rally in stock and bond markets and sending the euro plunging.

But in light of Europe’s underlying problems of stagnant growth, high debt and rigid labor markets, ECB President Mario Draghi suggested the central bank’s largess alone won’t be enough to right its economy.

“What monetary policy can do is create the basis for growth,” he said. “But for growth to pick up, you need investment; for investment, you need confidence; and for confidence, you need structural reform.”

The reactions to the central bank’s move rippled widely through the world’s trading floors, corporate boardrooms and European capitals. “It’s one piece of getting Europe back to growth, and we should see an impact,” Joe Jimenez, chief executive of drug giant Novartis said in an interview in Davos, Switzerland, where the political and economic elite are gathered for meetings of the World Economic Forum.