The euro has recovered slightly after hitting a 12-year low.
The single currency, which has lost roughly a quarter of its value against the US dollar since mid-2014, rose 0.9% to $1.0595 after earlier hitting its lowest level since January 2003.
Many investors say the weakness in the currency, which suffered its biggest weekly fall since September 2011 last week, has been overdone.
Comments by Italy's central bank governor that the euro had fallen faster than the European Central Bank expected contributed to the currency's rise today as the ECB launched quantitative easing.
The U.S. dollar index, which measures it against a basket of currencies, fell 0.8%.
Italian governor Ignazio Visco is also a member of the ECB Governing Council.
He told a conference over the weekend that the euro had weakened faster than expected since the ECB first hinted at the programme of money-printing last year.