THE Bendigo Health emergency department treated six heatstroke patients and five cases of dehydration during the heatwave last week.
A Bendigo Health spokesman said overall presentation numbers were down but the severity of the cases caused concern.
He said many of the affected patients suffered from multi-organ failure and required intensive care and resuscitation.
There were no cases of heat-related illness presented to the department on January 14 or January 19.
The department was presented with three cases of dehydration and one case of heatstroke on January 16.