Walgreen (NASDAQ:WBA) this morning reported fiscal 2014 third-quarter earnings that came in shy of Wall Street's estimates. For the period ended May 31, Walgreen generated a profit of $0.91 per diluted share. This was a 7% increase from the same period of 2013 in which the pharmacy chain posted a profit of $0.85 per diluted share. Even so, it was below analyst estimates for earnings per share of $0.94. Walgreen's third-quarter revenue, on the other hand, came in at $19.4 billion, up 5.9% from $18.3 billion in the year-ago period and in line with the Street's expectations.

Walgreen's stake in European drugstore chain Alliance Boots contributed $0.15 per diluted share to the company's adjusted earnings in the quarter. As a result, the company now expects second-year "synergies" from its strategic partnership with Alliance Boots to the tune of $400 million to $450 million, up from its prior guidance of $375 million to $425 million.

The pharmacy retailer said third-quarter adjusted earnings also benefited from a lower income tax. Additionally, front-end comparable sales, or sales excluding pharmacy-related purchases, increased 2.2% in the quarter, despite a decrease in traffic at stores open at least a year. Total same-store sales climbed 4.8%. Prescription sales increased 8.4% year over year and accounted for 64.4% of Walgreen's revenue in the period.

Shares of Walgreen's were trading down by more than 1% before the market opened on Tuesday.