Increasing weakness occurring over several days, involving the upper and lower limbs, and progressing to symmetrical paresis is a clinical presentation that raises many diagnostic issues. When faced with these circumstances most clinicians opt for a range of neurological possibilities. However, metabolic possibilities are equally important and are eminently treatable. There are a variety of reasons why potassium depletion presents as paralysis in Aboriginal Australians. The cause may not be apparent, although careful questioning may unearth clues that can lead to a diagnosis. Once the potassium level has been measured in the blood the diagnosis becomes obvious, but until that time the presentation can be confusing. Early serum potassium measurement is recommended with this clinical picture.