March 25 (Reuters) - Walgreen Co, operator of the largest U.S. drugstore chain, on Tuesday reported a rise in quarterly sales but said a slowdown in the introduction of higher-profit generic medicines cut into its gross profit margin.
Net income slipped to $754 million, or 78 cents per share, in the second quarter ended Feb. 28 from $756 million, or 79 cents per share, a year earlier. Excluding one-time costs, Walgreen had a profit of 91 cents a share.
The company's gross profit margin fell 1.3 percentage points to 28.8 percent of sales. Sales rose 5.1 percent to $19.61 billion.
(Reporting by Phil Wahba in New York; Editing by Lisa Von Ahn)