A shop selling medicines and related products. The term 売薬 refers to over-the-counter or patent medicines, so 売薬店 emphasizes a store dealing in such items. In modern usage, 薬局 or ドラッグストア are more common, but 売薬店 is still understood.
See also: 売薬
I bought cold medicine at the drugstore in front of the station.
Compound of 売薬 (baiyaku, 'patent medicine') + 店 (ten, 'shop'). The term reflects a historical focus on selling ready-made medicines rather than dispensing prescriptions.