diff --git a/htdocs/product/class/product.class.php b/htdocs/product/class/product.class.php
index 7f8de67a96a..b7647340ee9 100644
--- a/htdocs/product/class/product.class.php
+++ b/htdocs/product/class/product.class.php
@@ -496,7 +496,7 @@ class Product extends CommonObject
 	 *
 	 * @var array
 	 */
-	public $sousprods;
+	public $sousprods = array();
 
 	/**
 	 * Path of subproducts. Build from ->sousprods with get_arbo_each_prod()