DEERFIELD, Ill. — Shares of Walgreen Co. fell to their lowest price in almost five years today after the drugstore operator reported disappointing revenue in its fiscal fourth quarter, pointing to promotions that failed to pay off.

Walgreen said cost cuts and greater sales lifted its profit 12 percent for the quarter. But its revenue fell short of expectations, and the company said it engaged in too many discounts and promotions as it tried to ramp up sales in the face of difficult economic conditions. Customers did not pick up as many impulse items as Walgreens expected.

In morning trading, the stock fell $1.91, or 5.8 percent, to $30.82, and reached a low of $30.78. Walgreen shares last reached that level on Oct. 1, 2003. Profit for the quarter ended Aug. 31 increased to $443 million, or 45 cents per share, from $396.5 million, or 40 cents per share a year earlier.

The company said it remains committed to its efforts to buy California-based rival Longs Drug Stores Corp. Walgreen has offered $2.8 billion, or $75 per share, for the company, which would give Walgreen a larger presence in California and Hawai'i. Longs management prefers a bid from CVS Caremark Corp. worth $2.7 billion, or $71.50 per share, which has already received regulatory approval.