A liquid-collection canister for collecting liquid from a tissue site to which reduced pressure treatment is applied, the canister comprising: an outer shell; an inner liner positionable within the outer shell such that at least one gas-communication pathway is created between the inner liner and the outer shell, the inner liner defining a liquid collection chamber, the inner liner further including at least one aperture to allow gaseous communication between the liquid collection chamber and the gas-communication pathway; and a liquid air separator positioned over the at least one aperture to substantially prevent liquid passing through the aperture, characterised in that:- the outer shell is substantially rectangular prism shaped; the inner liner includes a plurality of walls and is substantially rectangular prism shaped; the at least one gas-communication pathway further comprises a first gas-communication pathway and a second gas-communication pathway, the first gas-communication pathway positioned between a first wall of the plurality of walls and the outer shell, the second gas-communication pathway positioned between a second wall of the plurality of walls and the outer shell; the at least one aperture further comprising a first aperture and a second aperture, the first aperture disposed in the first wall between the first gas-communication pathway and the liquid collection chamber, the second aperture disposed in the second wall between the second gas-communication pathway and the liquid collection chamber. an outer shell; an inner liner positionable within the outer shell such that at least one gas-communication pathway is created between the inner liner and the outer shell, the inner liner defining a liquid collection chamber, the inner liner further including at least one aperture to allow gaseous communication between the liquid collection chamber and the gas-communication pathway; and a liquid air separator positioned over the at least one aperture to substantially prevent liquid passing through the aperture, characterised in that:- the outer shell is substantially rectangular prism shaped; the inner liner includes a plurality of walls and is substantially rectangular prism shaped; the at least one gas-communication pathway further comprises a first gas-communication pathway and a second gas-communication pathway, the first gas-communication pathway positioned between a first wall of the plurality of walls and the outer shell, the second gas-communication pathway positioned between a second wall of the plurality of walls and the outer shell; the outer shell is substantially rectangular prism shaped; the inner liner includes a plurality of walls and is substantially rectangular prism shaped; the at least one gas-communication pathway further comprises a first gas-communication pathway and a second gas-communication pathway, the first gas-communication pathway positioned between a first wall of the plurality of walls and the outer shell, the second gas-communication pathway positioned between a second wall of the plurality of walls and the outer shell; the at least one aperture further comprising a first aperture and a second aperture, the first aperture disposed in the first wall between the first gas-communication pathway and the liquid collection chamber, the second aperture disposed in the second wall between the second gas-communication pathway and the liquid collection chamber.