diff --git a/Jobs/ZUGFeRD/EmailFunctions.vb b/Jobs/ZUGFeRD/EmailFunctions.vb
index 8cdc51f8..bbf6e7de 100644
--- a/Jobs/ZUGFeRD/EmailFunctions.vb
+++ b/Jobs/ZUGFeRD/EmailFunctions.vb
@@ -113,10 +113,14 @@ Namespace ZUGFeRD
 
             If pParameter1.IsNullOrEmpty Then
                 pParameter1 = ""
+            Else
+                pParameter1 = pParameter1.Replace("'", "''")
             End If
 
             If pParameter2.IsNullOrEmpty Then
                 pParameter2 = ""
+            Else
+                pParameter2 = pParameter2.Replace("'", "''")
             End If
 
             Try