Europe's single currency has climbed 13 percent so far this year against the dollar, as it benefited from political dysfunction in Washington and the Federal Reserve's gradual monetary tightening pace. A strong euro is a headwind for the export-driven euro zone economy.
Instead of the surging euro, Draghi, in his speech at the Jackson Hole, Wyoming central banker's conference, instead focused on other aspects such as a solid global recovery.
"Primarily the dynamic that traders are betting on now is that the European Central Bank is not concerned about the euros strength despite the impact that the euro is having on core inflation and growth metrics throughout the euro area," said Karl Schamotta, director of global market strategy at Cambridge Global Payments in Toronto.
He added that traders had expected Draghi to jawbone the currency downward, following up particularly on the minutes of the last meeting, "in which it was very clear that the governing council had become increasingly concerned about the euros strength."
The euro hit a high of $1.1940, its strongest level since January 2015. It was last at $1.1921, up 1.05 percent on the day, its best daily percentage gain in two months.
Against the yen, the dollar fell 0.22 percent to 109.30 yen, while the dollar index slid to 92.542, down 0.8 percent.
"At this point, there isn't too much for Yellen to add," said currency strategist Sireen Harajli of Mizuho Corporate Bank in New York.
"The FOMC (Federal Open Market Committee) has been very clear in terms of communicating their intention to continue tightening policy very gradually, and I don't think they see anything to change that view."
Instead, Yellen focused on U.S. regulations, saying those put in place after the 2007-2009 crisis had strengthened the financial system without impeding economic growth, and any future changes should remain modest.