diff --git a/htdocs/product/class/product.class.php b/htdocs/product/class/product.class.php
index 22c6aa0e6c1..b9ad2991738 100644
--- a/htdocs/product/class/product.class.php
+++ b/htdocs/product/class/product.class.php
@@ -431,7 +431,7 @@ class Product extends CommonObject
 		$this->ref = dol_string_nospecial(trim($this->ref));
 		$this->libelle = trim($this->libelle);
 		$this->description = trim($this->description);
-		$this->note = trim($this->note);
+		$this->note = (isset($this->note)? trim($this->note):"null");
 		$this->weight = price2num($this->weight);
 		$this->weight_units = trim($this->weight_units);
 		$this->length = price2num($this->length);