diff --git a/plugins/mysql/mysql_connections_per_user b/plugins/mysql/mysql_connections_per_user
index 28552d4b..9b4a96e7 100755
--- a/plugins/mysql/mysql_connections_per_user
+++ b/plugins/mysql/mysql_connections_per_user
@@ -100,6 +100,9 @@ sub print_graph_data() {
         if($print_user eq "root") {
             $print_user = "root_";
         }
+        if (  $print_user =~ /[^A-Za-z0-9]/ ) {
+            $print_user =~ s/[^A-Za-z0-9]/_/;
+        }
         print "$print_user.value $counts{$user}\n";
     }
     my $other = $numthreads - $total;
@@ -137,9 +140,13 @@ EOM
         if($print_user eq "root") {
             $print_user = "root_";
         }
+        if (  $print_user =~ /[^A-Za-z0-9]/ ) {
+            $print_user =~ s/[^A-Za-z0-9]/_/;
+        }
+
         print <<EOM;
 $print_user.label $user
-$print_user.info Number of connexions used by user $print_user
+$print_user.info Number of connexions used by user $user
 EOM
         print "$print_user.draw ";