Walgreen Co. (WAG) on Thursday said same-store sales rose 3.7% in August, lead by growth in the pharmacy section, but fell shy of analysts' expectations.

Analysts polled by Thomson Reuters expected same-store sales growth of 3.8% for the month.

Same-store sales for the fiscal fourth-quarter, which ended Aug. 31, rose 5.6%. Total sales for the quarter rose 6.2% to $19.06 billion, topping analysts' projections for $18.995 billion.

For August, Walgreen's pharmacy same-store sales rose 5%. Excluding calendar-day shifts, pharmacy same-store sales rose 7.1%, with a negative impact of 1.8 percentage points owing to generic drug introductions in the past year. Analysts had forecast pharmacy same-store sales growth of 5.5%.

In the front of the store, same-store sales rose 1.4% in August, topping analysts' views for growth of 1%. Customer traffic fell 1.7%, but basket size increased by 3.1%.

Walgreen said August total drugstore sales rose 3.6% to $6.39 billion.

Walgreen is in the midst of acquiring the rest of European drug giant Alliance Boots GmbH, and it is also trying to restore investor confidence after unexpectedly slashing its financial outlook following a botched forecast tied to drug-reimbursement rates.

Write to Tess Stynes at tess.stynes@wsj.com

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