DEERFIELD, Ill. — Making a major investment in its home market, Walgreen Co. plans to remodel many of its 142 drug stores in Chicago, quadruple the number of “food oasis” stores there and expand its downtown office space.

Making a major investment in its home market, Walgreen Co. plans to remodel many of its 142 drug stores in Chicago, quadruple the number of “food oasis” stores there and expand its downtown office space.

Under the Chicago Hometown Investment Initiative, Walgreens aims to double the number of food oasis stores in the city by 2012 and then double that number again in 2013 to reach a total of nearly 50. The chain now has 11 such stores, which offer a bigger selection of groceries and fresh food in Chicago communities with a dearth of supermarkets.

Walgreens also plans to open at least five more stores in the city over the next two years and redesign numerous other outlets there. The retailer, too, has launched its Web Pickup service at nearly 300 stores in metropolitan Chicago and plans to finish a full rollout to 480 outlets in August.