diff --git a/htdocs/admin/syslog.php b/htdocs/admin/syslog.php
index cbe1aa16322..e8436730ebe 100644
--- a/htdocs/admin/syslog.php
+++ b/htdocs/admin/syslog.php
@@ -51,6 +51,10 @@ if ($action == 'set')
     $res = dolibarr_del_const($db,"SYSLOG_SYSLOG_ON",0);
     $res = dolibarr_del_const($db,"SYSLOG_FIREPHP_ON",0);
 
+    $syslog_file_on=0;
+    $syslog_syslog_on=0;
+    $syslog_firephp_on=0;
+
 	if (! $error && GETPOST("filename"))
 	{
 		$filename=GETPOST("filename");