Retail health clinics are a booming business in Houston.

Take Care Health Systems, a subsidiary of Walgreen Co., plans to open 3 new in-store clinics in the Houston, Spring, and Woodlands area this summer, adding to the 9 clinics already operating here. Take Care currently operates 172 convenient-care clinics in 14 states, and plans to have more than 400 clinics open by the end of 2008.

MinuteClinic, a subsidiary of CVS Corp., has opened three new clinics in the Houston area in 2008, bringing its total to 11. MinuteClinic's new locations are in Humble, Pearland and on Memorial Drive. MinuteClinic has more than 500 clinics nationwide and said earlier this year that it plans to open up to 250 new clinics this year.

Houston-based competitor is RediClinic LLC, has opened eight new clinics in H-E-B grocery stores since February 2007, for a total of 14 clinics operating in the Houston area. In addition to its H-E-B clinics, RediClinic will be partnering with Wal-Mart Stores Inc. to operate 200 of the 400 new clinics that Wal-Mart has announced it plans to open over the next two to three years.

In 2005, Wal-Mart began leasing in-store space to independent health care providers to operate the clinics. In the Houston area, Wal-Mart has six in-store clinics operated by Houston-based My Healthy Access Inc. The retail giant currently has about 80 clinics operating in its stores.

Earlier this year, Wal-Mart began opening clinics under its own brand name. The company has said it intends to contract with local hospitals and other organizations such as RediClinic to open as many as 2,000 in-store clinics over the next five to seven years.

Retail clinics are usually staffed with qualified licensed nurse practitioners working under the supervision of a physician or hospital. The clinics treat common illnesses and provide routine physicals and flu shots and vaccinations as well as screenings for such conditions as diabetes and high blood pressure. Charges for these services usually fall within a $40- to $60 range at most clinics, which treat uninsured and insured patients.