diff --git a/htdocs/core/class/html.formmail.class.php b/htdocs/core/class/html.formmail.class.php
index f2697bc3873..469b6dabe29 100644
--- a/htdocs/core/class/html.formmail.class.php
+++ b/htdocs/core/class/html.formmail.class.php
@@ -1551,7 +1551,7 @@ class FormMail extends Form
 
 					if (!empty($extrafields->attributes[$product->table_element]['label']) && is_array($extrafields->attributes[$product->table_element]['label']) && count($extrafields->attributes[$product->table_element]['label']) > 0) {
 						foreach ($extrafields->attributes[$product->table_element]['label'] as $key => $label) {
-							$substit_line['__PRODUCT_EXTRAFIELD_'.strtoupper($key).'__'] = $product->array_options['options_'.$key];
+							isset($product->array_options['options_'.$key]) ? $substit_line['__PRODUCT_EXTRAFIELD_'.strtoupper($key).'__'] = $product->array_options['options_'.$key] : '';
 						}
 					}
 				}