The unit was started in 1991 when Walgreens decided to expand on the services provided by its mail service division .
Walgreens Health Services ( WHS ) is a business unit of Walgreens .
The unit was started in 1991 when Walgreens decided to expand on the services provided by Walgreens ' mail service division .
Walgreens Health Services ( WHS ) is a business unit of Walgreens .