The dollar failed to hold onto its gains against a basket of currencies on Thursday, the day after the Federal Reserve said it expected inflation to rise this year.
The greenback also pared its gains against the yen as U.S. and European stocks fell.
In January, the dollar clocked in its worst monthly performance since March 2016, falling 3.25 percent.
The Fed left interest rates unchanged on Wednesday but bolstered expectations that they would continue to rise by saying inflation was likely to accelerate this year.
The dollar index, which tracks the greenback against six major currencies, rose briefly after the announcement and climbed again overnight in Asian trading.
The greenback last traded hands down 0.52 percent at 88.67.
The dollar also pared its gains against the yen in morning trading. It was last up 0.23 percent at 109.42 yen, compared with 109.74 yen at around 6:30 a.m. EST.
The dollar hit a four-month low of 108.27 against the yen on Friday.
David Gilmore, a partner at Foreign Exchange Analytics in Connecticut, said a broad selloff in world stocks on Thursday had made investors cautious. U.S. stocks opened lower after a string of lackluster earnings and the Fed's comments on Wednesday.
"Markets are on pins and needles about stocks, given the correction this week," he said. "Very often we see the yen strengthen when stock prices go down."
Traders are looking ahead to the U.S. government's jobs report on Friday.