diff --git a/phpBB/docs/CHANGELOG.html b/phpBB/docs/CHANGELOG.html
index ded991fa32..ed177b6d18 100644
--- a/phpBB/docs/CHANGELOG.html
+++ b/phpBB/docs/CHANGELOG.html
@@ -146,6 +146,7 @@
 		<li>[Change] Show login attempt CAPTCHA option in the captcha plugin module.</li>
 		<li>[Change] It is no longer possible to persist a solution for the login CAPTCHA.</li>
 		<li>[Change] SQLite is no longer autoloaded by the installer. (Bug #56105)</li>
+		<li>[Change] Friends and foes will not show up as private message rule options if their respective UCP modules are disabled. (Bug #51155)</li>
 	</ul>
 
 	<a name="v305"></a><h3>1.ii. Changes since 3.0.5</h3>
diff --git a/phpBB/includes/ucp/ucp_pm_options.php b/phpBB/includes/ucp/ucp_pm_options.php
index e80c0672cf..58c2d087c8 100644
--- a/phpBB/includes/ucp/ucp_pm_options.php
+++ b/phpBB/includes/ucp/ucp_pm_options.php
@@ -637,12 +637,29 @@ function define_action_option($hardcoded, $action_option, $action_lang, $folder)
 function define_rule_option($hardcoded, $rule_option, $rule_lang, $check_ary)
 {
 	global $template;
+	global $module;
+
+	$exclude = array();
+
+	if (!$module->loaded('zebra', 'friends'))
+	{
+		$exclude[RULE_IS_FRIEND] = true;
+	}
+
+	if (!$module->loaded('zebra', 'foes'))
+	{
+		$exclude[RULE_IS_FOE] = true;
+	}
 
 	$s_rule_options = '';
 	if (!$hardcoded)
 	{
 		foreach ($check_ary as $value => $_check)
 		{
+			if (isset($exclude[$value]))
+			{
+				continue;
+			}
 			$s_rule_options .= '<option value="' . $value . '"' . (($value == $rule_option) ? ' selected="selected"' : '') . '>' . $rule_lang[$value] . '</option>';
 		}
 	}