Energy prices, which have declined in four of the past five months, dropped 2.6 percent with a 4.4 percent drop in gasoline prices in the month. That partly erases the 9.1 percent jump in gasoline prices in February.
Food prices were unchanged in the month after rising 0.1 percent in February, the department said.
Core prices, which excludes the volatile categories of food and energy, rose 0.1 percent in the month, which put the 12-month rate at 1.9 percent.
At 1.5 percent on a 12-month basis, the inflation rate for all items is well below the 2 percent target rate set by the U.S. Federal Reserve.