Method and device for scavenging tainted escape gas at a location proximate the patient's mouth (24) before that gas diffuses into, or otherwise reaches the personal breathing space (32, 35) of attending health care providers (38, 39). The scavenging device (50) includes, but is not limited to a suction arrangement (52) suspendable from a patient's nasal mask (40) used for administering gaseous analgesia or anesthetic such as nitrous oxide to the patient (20). A suction inlet (54) is positionable proximate the patient's mouth (24) and an exhaust outlet (56) is provided that is interconnectable with a vacuum source (46).