diff --git a/htdocs/product/class/product.class.php b/htdocs/product/class/product.class.php
index 07aaf32cbb3..e47af8517de 100644
--- a/htdocs/product/class/product.class.php
+++ b/htdocs/product/class/product.class.php
@@ -763,7 +763,7 @@ class Product extends CommonObject
 			$sql.= ", duration = '" . $this->db->escape($this->duration_value . $this->duration_unit) ."'";
 			$sql.= ", accountancy_code_buy = '" . $this->db->escape($this->accountancy_code_buy)."'";
 			$sql.= ", accountancy_code_sell= '" . $this->db->escape($this->accountancy_code_sell)."'";
-			$sql.= ", desiredstock = " . ((isset($this->desiredstock) && $this->desiredstock != '') ? $this->desiredstock : "null");
+			$sql.= ", desiredstock = " . ((isset($this->desiredstock) && is_numeric($this->desiredstock)) ? $this->desiredstock : "null");
 			$sql.= ", cost_price = " . ($this->cost_price != '' ? $this->db->escape($this->cost_price) : 'null');
 	        $sql.= ", fk_unit= " . (!$this->fk_unit ? 'NULL' : $this->fk_unit);
 	        $sql.= ", price_autogen = " . (!$this->price_autogen ? 0 : 1);