Walgreen Co. (NYSE: WAG) announced a multi-year pharmacy network agreement with Express Scripts on Thursday morning after a seven-month split.

The agreement will once again allow customers of Express Scripts fill their prescriptions at Walgreens pharmacy stores, according to the Chicago Tribune. The two were unable to reach an agreement in January when the contract ran up, which had a considerable negative effect on Walgreen.

Express Scripts made up more than 10 percent of the prescriptions Walgreen filled in 2011, with an estimated value of $5 billion. The loss of Express Scripts' business dropped Walgreen's share price more than 30 percent in 2012.

In early market trading, Walgreen is up more than 12 percent, or $3.75, to $34.72.

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