Abstract: A ventilator for withdrawing foul air from a lavatory pan has, within a housing (16), a duct (11) for connection between the discharge pipe (31) of the lavatory flushing assembly and the flush pipe (33) of the lavatory pan. An extractor fan (41) is provided in the housing (16) for withdrawing air from the duct (11) by way of an air passage (28) therein and expelling it through an exhaust pipe (47) to atmosphere outside the lavatory. The air passage (28) may be opened or closed by a valve (27). The fan (41) may be switched on when the valve (27) is open. When the lavatory pan is flushed, water passing through the duct (11) moves a cup (25) connected to the valve (27) so as to close the valve (27) and switch off the fan (41).