Walgreen Co. has seen great success with its program that sends text message alerts to customers when their prescriptions are ready to be picked up. More than two million consumers routinely receive those messages, Walgreens says.

Building on this mobile momentum, Walgreens has introduced another text service, this one for prescription refills. A customer signs up for the new service in-store or online. When it’s time for a prescription to be refilled, Walgreens sends the consumer a text message with the details. She replies with the word “refill” and her local pharmacist refills the prescription. Then the retailer sends her a text when the medication is ready to be picked up.

Mobile prescription services are popular at Walgreens, No. 42 in the Internet Retailer Mobile Commerce Top 300. 25% of all online prescription refills stem from the company’s mobile apps, the merchant reports. The apps include a bar code scanner that allows a customer to use her smartphone camera to scan the code on a prescription bottle to automatically order a refill.

“We’ve driven strong adoption and customer engagement through our mobile applications, and these mobile pharmacy features are also great tools for helping people manage their health,” says Sona Chawla, the retailer’s president of e-commerce. “This is another way we’re extending the access to Walgreens pharmacy to patients on the go and helping them stay well.”

Walgreens, which operates 7,760 drugstores, is No. 73 in the Internet Retailer Top 500 Guide.