diff --git a/glucometer_graphs.py b/glucometer_graphs.py
index b8c700b..d3b7dc0 100755
--- a/glucometer_graphs.py
+++ b/glucometer_graphs.py
@@ -704,7 +704,7 @@ def verify_units(units = None, high = None, low = None):
   ''' Standardise units for output and for the A1c calculations '''
   if re.search('mg', units, flags=re.IGNORECASE) is not None:
     units = UNIT_MGDL
-  elif re.search('mg', units, flags=re.IGNORECASE) is not None:
+  elif re.search('mm', units, flags=re.IGNORECASE) is not None:
     units = UNIT_MMOLL
   elif isinstance(high, (int, float)) or isinstance(low, (int, float)):
     ''' If units are not specified by the arguments or calling function, let's assume they are