diff --git a/inc/commoninjectionlib.class.php b/inc/commoninjectionlib.class.php
index a47199ce..1ffaa11f 100644
--- a/inc/commoninjectionlib.class.php
+++ b/inc/commoninjectionlib.class.php
@@ -860,7 +860,11 @@ private function setValueForItemtype($itemtype, $field, $value, $fromdb = false)
          }
 
       } else { // First value
-         $this->values[$itemtype][$field] = $value;
+         if (is_null($value)) {
+            $this->values[$itemtype][$field] = "NULL";
+         } else {
+            $this->values[$itemtype][$field] = $value;
+         }
       }
    }