The dollar was on track for its biggest daily drop in more than five weeks against the yen after a sharp slide in Japanese stocks and weak Chinese factory activity data.
The dollar rallied to trade at a fresh 4 1/2-year high against the yen after Fed Chairman Ben Bernanke warned that holding interest rates too low for too long has its risks.
The U.S. dollar fell against the euro on Tuesday after St. Louis Federal Reserve President James Bullard dented expectations the U.S. central bank may taper its bond purchases.
The U.S. dollar fell against the euro and yen on Monday as traders pared back expectations Federal Reserve Chairman Ben Bernanke would hint at tapering bond purchases this week.
The Australian currency has been falling sharply and selling the Aussie dollar for the appreciating Mexican peso is becoming an increasingly popular trade, said an analyst.
The U.S. dollar recovered to trade higher against the euro and yen late Thursday afternoon in a volatile session that saw the U.S. currency swing between gains and losses.
The yen fell against the dollar on Tuesday for a fourth straight session, hitting its lowest level in 4 1/2 years as signs that the U.S. economy is improving.
The dollar gained for a third straight session against the yen and euro on Monday as data showing a rise in U.S. retail sales assuaged fears of an economic slowdown.
The U.S. dollar skyrocketed to its highest level against the Japanese yen in over four years on Thursday, piercing the key technical and psychological 100 yen-per-dollar mark.
The euro rose against the dollar after an unexpected rise in German industrial output was seen making a near-term euro zone interest rate cut less likely.
The euro firmed across the board on Tuesday after data showing German industrial orders beat forecasts, but the prospect of further monetary easing could limit its gains.
The U.S. dollar rose for a third straight session against the yen on Monday and looked set to make another run at the 100 yen level on renewed optimism about the U.S. economy.
The dollar surged more than 1 percent against the yen on Friday after strong U.S. April jobs data fueled optimism the U.S. economy may be more resilient than some had feared.
The euro fell sharply against the dollar in choppy trading on Thursday after European Central Bank President Mario Draghi said the bank is ready for negative deposit rates.
The U.S. dollar pared its losses against the yen on Wednesday after the U.S. Federal Reserve said it will stick to its plan to buy $85 billion in bonds each month.