Carbon monoxide poisoning represents a potentially preventable and reversible cause of mortality and morbidity if sources and cases can be identified. The elderly have been shown to be particularly at risk. Concerns continue to be raised about potential unrecognised cases of carbon monoxide poisoning. These concerns arise from difficulties in knowing who to suspect as a potential victim of poisoning as well as how, when and what to test. In general carbon monoxide has no helpful unique clinical presentation and is known to mimic common illnesses as well as exacerbate established diseases. As a gas it is undetectable by the human senses and is potentially present in most households. This paper reviews the issues associated with carbon monoxide poisoning including pointers to early diagnosis and discussion of pathophysiology and management.