diff --git a/wp-admin/admin-functions.php b/wp-admin/admin-functions.php
index 20688f7cec..3ff4d66e9e 100644
--- a/wp-admin/admin-functions.php
+++ b/wp-admin/admin-functions.php
@@ -983,7 +983,7 @@ function list_meta($meta) {
 			$style .= ' hidden';
 
 		if ( is_serialized($entry['meta_value']) ) {
-			if ( 's' == $entry['meta_value']{0} ) {
+			if ( is_serialized_string($entry['meta_value']) ) {
 				// this is a serialized string, so we should display it
 				$entry['meta_value'] = maybe_unserialize($entry['meta_value']);
 			} else {
@@ -1068,7 +1068,7 @@ function add_meta($post_ID) {
 
 	$metakeyselect = $wpdb->escape(stripslashes(trim($_POST['metakeyselect'])));
 	$metakeyinput = $wpdb->escape(stripslashes(trim($_POST['metakeyinput'])));
-	$metavalue = prepare_data(stripslashes((trim($_POST['metavalue']))));
+	$metavalue = maybe_serialize(stripslashes((trim($_POST['metavalue']))));
 	$metavalue = $wpdb->escape($metavalue);
 
 	if ( ('0' === $metavalue || !empty ($metavalue)) && ((('#NONE#' != $metakeyselect) && !empty ($metakeyselect)) || !empty ($metakeyinput)) ) {
@@ -1100,8 +1100,8 @@ function delete_meta($mid) {
 
 function update_meta($mid, $mkey, $mvalue) {
 	global $wpdb;
-	if ( is_serialized(stripslashes($mvalue)) ) // $mvalue looks to be already serialized, so we should serialize it again to prevent the data from coming out in a different form than it came in
-		$mvalue = serialize($mvalue);
+	$mvalue = maybe_serialize(stripslashes($mvalue));
+	$mvalue = $wpdb->escape($mvalue);
 	$mid = (int) $mid;
 	return $wpdb->query("UPDATE $wpdb->postmeta SET meta_key = '$mkey', meta_value = '$mvalue' WHERE meta_id = '$mid'");
 }
diff --git a/wp-admin/options.php b/wp-admin/options.php
index aaf79cb4f2..87db8e9c36 100644
--- a/wp-admin/options.php
+++ b/wp-admin/options.php
@@ -128,7 +128,7 @@ $options = $wpdb->get_results("SELECT * FROM $wpdb->options ORDER BY option_name
 foreach ( (array) $options as $option) :
 	$disabled = '';
 	if ( is_serialized($option->option_value) ) {
-		if ( 's' == $option->option_value{0} ) {
+		if ( is_serialized_string($option->option_value) ) {
 			// this is a serialized string, so we should display it
 			$value = wp_specialchars(maybe_unserialize($option->option_value), 'single');
 			$options_to_update[] = $option->option_name;
diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index a1d76ec665..0e472ad7ef 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -257,7 +257,7 @@ function update_option($option_name, $newvalue) {
 	}
 
 	$_newvalue = $newvalue;
-	$newvalue = prepare_data($newvalue);
+	$newvalue = maybe_serialize($newvalue);
 
 	wp_cache_set($option_name, $newvalue, 'options');
 
@@ -279,7 +279,7 @@ function add_option($name, $value = '', $description = '', $autoload = 'yes') {
 	if ( false !== get_option($name) )
 		return;
 
-	$value = prepare_data($value);
+	$value = maybe_serialize($value);
 
 	wp_cache_set($name, $value, 'options');
 
@@ -301,7 +301,7 @@ function delete_option($name) {
 	return true;
 }
 
-function prepare_data($data) {
+function maybe_serialize($data) {
 	if ( is_string($data) )
 		$data = trim($data);
 	elseif ( is_array($data) || is_object($data) )
diff --git a/wp-includes/post.php b/wp-includes/post.php
index e790a03609..1584a25574 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -231,7 +231,7 @@ function add_post_meta($post_id, $key, $value, $unique = false) {
 
 	$post_meta_cache[$post_id][$key][] = $value;
 
-	$value = prepare_data($value);
+	$value = maybe_serialize($value);
 	$value = $wpdb->escape($value);
 
 	$wpdb->query("INSERT INTO $wpdb->postmeta (post_id,meta_key,meta_value) VALUES ('$post_id','$key','$value')");
@@ -310,11 +310,11 @@ function update_post_meta($post_id, $key, $value, $prev_value = '') {
 	$post_id = (int) $post_id;
 
 	$original_value = $value;
-	$value = prepare_data($value);
+	$value = maybe_serialize($value);
 	$value = $wpdb->escape($value);
 
 	$original_prev = $prev_value;
-	$prev_value = prepare_data($prev_value);
+	$prev_value = maybe_serialize($prev_value);
 	$prev_value = $wpdb->escape($prev_value);
 
 	if (! $wpdb->get_var("SELECT meta_key FROM $wpdb->postmeta WHERE meta_key = '$key' AND post_id = '$post_id'") ) {
diff --git a/wp-includes/user.php b/wp-includes/user.php
index 8c4c58ad65..62d20a7e31 100644
--- a/wp-includes/user.php
+++ b/wp-includes/user.php
@@ -116,7 +116,7 @@ function update_usermeta( $user_id, $meta_key, $meta_value ) {
 
 	// FIXME: usermeta data is assumed to be already escaped
 	$meta_value = stripslashes($meta_value);
-	$meta_value = prepare_data($meta_value);
+	$meta_value = maybe_serialize($meta_value);
 	$meta_value = $wpdb->escape($meta_value);
 
 	if (empty($meta_value)) {