diff --git a/wp-admin/includes/post.php b/wp-admin/includes/post.php
index e611287dc3..692dc58df7 100644
--- a/wp-admin/includes/post.php
+++ b/wp-admin/includes/post.php
@@ -559,7 +559,9 @@ function add_meta( $post_ID ) {
 
 	$metakeyselect = isset($_POST['metakeyselect']) ? stripslashes( trim( $_POST['metakeyselect'] ) ) : '';
 	$metakeyinput = isset($_POST['metakeyinput']) ? stripslashes( trim( $_POST['metakeyinput'] ) ) : '';
-	$metavalue = isset($_POST['metavalue']) ? maybe_serialize( stripslashes( trim( $_POST['metavalue'] ) ) ) : '';
+	$metavalue = isset($_POST['metavalue']) ? maybe_serialize( stripslashes_deep( $_POST['metavalue'] ) ) : '';
+	if ( is_string($metavalue) )
+		$metavalue = trim( $metavalue );
 
 	if ( ('0' === $metavalue || !empty ( $metavalue ) ) && ((('#NONE#' != $metakeyselect) && !empty ( $metakeyselect) ) || !empty ( $metakeyinput) ) ) {
 		// We have a key/value pair. If both the select and the
@@ -686,7 +688,7 @@ function update_meta( $meta_id, $meta_key, $meta_value ) {
 	$post_id = $wpdb->get_var( $wpdb->prepare("SELECT post_id FROM $wpdb->postmeta WHERE meta_id = %d", $meta_id) );
 	wp_cache_delete($post_id, 'post_meta');
 
-	$meta_value = maybe_serialize( stripslashes( $meta_value ) );
+	$meta_value = maybe_serialize( stripslashes_deep( $meta_value ) );
 	$meta_id = (int) $meta_id;
 
 	$data  = compact( 'meta_key', 'meta_value' );