diff --git a/htdocs/core/class/commondocgenerator.class.php b/htdocs/core/class/commondocgenerator.class.php
index fadd0c02fde..c9865cffe59 100644
--- a/htdocs/core/class/commondocgenerator.class.php
+++ b/htdocs/core/class/commondocgenerator.class.php
@@ -497,8 +497,16 @@ abstract class CommonDocGenerator
 			$resarray['object_total_up'] = $totalUp;
 			$resarray['object_total_up_locale'] = price($resarray['object_total_up'], 0, $outputlangs);
 			if (method_exists($object, 'getTotalDiscount')) {
-				$resarray['object_total_discount'] = round(100 / $totalUp * $object->getTotalDiscount(), 2);
+				$totalDiscount=$object->getTotalDiscount();
+			} else {
+				$totalDiscount=0;
+			}
+			if (!empty($totalUp) && !empty($totalDiscount)) {
+				$resarray['object_total_discount'] = round(100 / $totalUp * $totalDiscount, 2);
 				$resarray['object_total_discount_locale'] = price($resarray['object_total_discount'], 0, $outputlangs);
+			} else {
+				$resarray['object_total_discount']='';
+				$resarray['object_total_discount_locale']='';
 			}
 		}