CAMP HILL, Pa. — Rite Aid Corp. saw same-store sales decline for the third straight month in June.

The drug store chain said Thursday that the four weeks ended June 26, same-store sales fell 2.5% from the prior-year period. June’s decrease followed declines of 1.7% in May and 1% in April, after the retailer posted flat results in March.

The bigger same-store decrease in June was fueled mainly by a drop-off in the pharmacy. Rite Aid said pharmacy same-store sales in the month slipped 3.1%, reflecting a 157-basis-point negative impact from new generic drug introductions. Prescriptions filled at comparable stores decreased 3.7% year over year.

Rite Aid reported a 1.1% decline in front-end same-stores sales for June.

Meanwhile, total drug store sales for June fell 3.3% to $1.91 billion from $1.97 billion a year earlier.

For the 17-week year-to-date period ended June 26, same-store sales dipped 1.4% versus the prior-year time span, including declines of 1.4% in the pharmacy and 1.2% in the front end. Prescriptions filled at comparable stores decreased 2.2% during the period.

Year-to-date drug store sales were down 2.4% to about $8.28 billion from $8.48 billion a year earlier.

As of June 26, Rite Aid operated 4,759 stores, down from 4,822 stores in the year-ago period.