diff --git a/htdocs/admin/dict.php b/htdocs/admin/dict.php
index 9d265d0240d..859ef271a85 100644
--- a/htdocs/admin/dict.php
+++ b/htdocs/admin/dict.php
@@ -2004,6 +2004,11 @@ if ($id > 0) {
 					$canbemodified = 1;
 				}
 
+				if ($tabname[$id] == "c_product_nature" && in_array($obj->code, array(0, 1))) {
+					$canbedisabled = 0;
+					$canbemodified = 0;
+					$iserasable = 0;
+				}
 				// Build Url. The table is id=, the id of line is rowid=
 				$rowidcol = $tabrowid[$id];
 				// If rowidcol not defined