diff --git a/system/core/Common.php b/system/core/Common.php
index 2fd5c58..d6a1fdb 100644
--- a/system/core/Common.php
+++ b/system/core/Common.php
@@ -135,7 +135,7 @@
 	 *
 	 * @param	string	the class name being requested
 	 * @param	string	the directory where the class should be found
-	 * @param	string	an optional argument to pass to the class constructor
+	 * @param	mixed	an optional argument to pass to the class constructor
 	 * @return	object
 	 */
 	function &load_class($class, $directory = 'libraries', $param = NULL)
diff --git a/system/core/Exceptions.php b/system/core/Exceptions.php
index 47d153f..5269096 100644
--- a/system/core/Exceptions.php
+++ b/system/core/Exceptions.php
@@ -231,7 +231,7 @@
 	 * @param	string	$message	Error message
 	 * @param	string	$filepath	File path
 	 * @param	int	$line		Line number
-	 * @return	string	Error page output
+	 * @return	void
 	 */
 	public function show_php_error($severity, $message, $filepath, $line)
 	{
diff --git a/system/core/compat/mbstring.php b/system/core/compat/mbstring.php
index f466e1c..1b2f2c6 100644
--- a/system/core/compat/mbstring.php
+++ b/system/core/compat/mbstring.php
@@ -68,7 +68,7 @@
 	 * @link	http://php.net/mb_strlen
 	 * @param	string	$str
 	 * @param	string	$encoding
-	 * @return	string
+	 * @return	int
 	 */
 	function mb_strlen($str, $encoding = NULL)
 	{
diff --git a/system/database/DB_forge.php b/system/database/DB_forge.php
index 7289235..3cb02ca 100644
--- a/system/database/DB_forge.php
+++ b/system/database/DB_forge.php
@@ -488,7 +488,7 @@
 	 *
 	 * @param	string	$table		Table name
 	 * @param	bool	$if_exists	Whether to add an IF EXISTS condition
-	 * @return	string
+	 * @return	mixed	(Returns a platform-specific DROP table string, or TRUE to indicate there's nothing to do)
 	 */
 	protected function _drop_table($table, $if_exists)
 	{
@@ -979,8 +979,8 @@
 	/**
 	 * Process indexes
 	 *
-	 * @param	string	$table
-	 * @return	string
+	 * @param	string	$table	Table name
+	 * @return	string[] list of SQL statements
 	 */
 	protected function _process_indexes($table)
 	{
diff --git a/system/database/drivers/ibase/ibase_forge.php b/system/database/drivers/ibase/ibase_forge.php
index 44bb24e..31352f1 100644
--- a/system/database/drivers/ibase/ibase_forge.php
+++ b/system/database/drivers/ibase/ibase_forge.php
@@ -91,7 +91,7 @@
 	 * Create database
 	 *
 	 * @param	string	$db_name
-	 * @return	string
+	 * @return	bool
 	 */
 	public function create_database($db_name)
 	{
diff --git a/system/libraries/Session/drivers/Session_redis_driver.php b/system/libraries/Session/drivers/Session_redis_driver.php
index d260f7b..e220a29 100644
--- a/system/libraries/Session/drivers/Session_redis_driver.php
+++ b/system/libraries/Session/drivers/Session_redis_driver.php
@@ -51,7 +51,7 @@
 	/**
 	 * phpRedis instance
 	 *
-	 * @var	resource
+	 * @var	Redis
 	 */
 	protected $_redis;
 
diff --git a/system/libraries/Table.php b/system/libraries/Table.php
index fef9bb0..50c5e35 100644
--- a/system/libraries/Table.php
+++ b/system/libraries/Table.php
@@ -435,7 +435,7 @@
 	/**
 	 * Set table data from a database result object
 	 *
-	 * @param	CI_DB_result	$db_result	Database result object
+	 * @param	CI_DB_result	$object	Database result object
 	 * @return	void
 	 */
 	protected function _set_from_db_result($object)