diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -419,6 +419,7 @@
     'DifferentialReleephRequestFieldSpecification' => 'applications/releeph/differential/DifferentialReleephRequestFieldSpecification.php',
     'DifferentialRemarkupRule' => 'applications/differential/remarkup/DifferentialRemarkupRule.php',
     'DifferentialReplyHandler' => 'applications/differential/mail/DifferentialReplyHandler.php',
+    'DifferentialReplyHandlerTestCase' => 'applications/differential/mail/__tests__/DifferentialReplyHandlerTestCase.php',
     'DifferentialRepositoryField' => 'applications/differential/customfield/DifferentialRepositoryField.php',
     'DifferentialRepositoryLookup' => 'applications/differential/query/DifferentialRepositoryLookup.php',
     'DifferentialResultsTableView' => 'applications/differential/view/DifferentialResultsTableView.php',
@@ -3102,6 +3103,7 @@
     'DifferentialProjectReviewersField' => 'DifferentialCustomField',
     'DifferentialRemarkupRule' => 'PhabricatorRemarkupRuleObject',
     'DifferentialReplyHandler' => 'PhabricatorMailReplyHandler',
+    'DifferentialReplyHandlerTestCase' => 'PhabricatorTestCase',
     'DifferentialRepositoryField' => 'DifferentialCoreCustomField',
     'DifferentialRepositoryLookup' => 'Phobject',
     'DifferentialResultsTableView' => 'AphrontView',
diff --git a/src/applications/differential/mail/DifferentialReplyHandler.php b/src/applications/differential/mail/DifferentialReplyHandler.php
--- a/src/applications/differential/mail/DifferentialReplyHandler.php
+++ b/src/applications/differential/mail/DifferentialReplyHandler.php
@@ -99,19 +99,29 @@
     $this->handleAction($mail->getCleanTextBody(), $mail->getAttachments());
   }
 
-  public function handleAction($body, array $attachments) {
+  public function extractCommand($body) {
     // all commands start with a bang and separated from the body by a newline
     // to make sure that actual feedback text couldn't trigger an action.
     // unrecognized commands will be parsed as part of the comment.
     $command = DifferentialAction::ACTION_COMMENT;
     $supported_commands = $this->getSupportedCommands();
-    $regex = "/\A\n*!(" . implode('|', $supported_commands) . ")\n*/";
+    $regex = "/(?:\A\s*|\n+\s*)!(".
+             implode('|', $supported_commands).
+             ")(?:\s*\z|\s*\n+)/";
+
     $matches = array();
     if (preg_match($regex, $body, $matches)) {
       $command = $matches[1];
       $body = trim(str_replace('!' . $command, '', $body));
     }
 
+
+    return array($command, $body);
+  }
+
+  public function handleAction($body, array $attachments) {
+    list($command, $body) = $this->extractCommand($body);
+
     $actor = $this->getActor();
     if (!$actor) {
       throw new Exception('No actor is set for the reply action.');
diff --git a/src/applications/differential/mail/__tests__/DifferentialReplyHandlerTestCase.php b/src/applications/differential/mail/__tests__/DifferentialReplyHandlerTestCase.php
new file mode 100644
--- /dev/null
+++ b/src/applications/differential/mail/__tests__/DifferentialReplyHandlerTestCase.php
@@ -0,0 +1,36 @@
+<?php
+
+final class DifferentialReplyHandlerTestCase extends PhabricatorTestCase {
+
+  public function testExtractCommand() {
+    $handler = new DifferentialReplyHandler();
+    list($command, $body) = $handler->extractCommand("!reject\ntext");
+    $this->assertEqual('reject', $command);
+    $this->assertEqual('text', $body);
+
+    list($command, $body) = $handler->extractCommand('!reject');
+    $this->assertEqual('reject', $command);
+    $this->assertEqual('', $body);
+
+    list($command, $body) = $handler->extractCommand("hello\n!reject");
+    $this->assertEqual('reject', $command);
+    $this->assertEqual('hello', $body);
+
+    list($command, $body) =
+      $handler->extractCommand('just chatting about !reject');
+    $this->assertEqual(DifferentialAction::ACTION_COMMENT, $command);
+    $this->assertEqual('just chatting about !reject', $body);
+
+    list($command, $body) = $handler->extractCommand('!reject is awesome');
+    $this->assertEqual(DifferentialAction::ACTION_COMMENT, $command);
+    $this->assertEqual('!reject is awesome', $body);
+
+    list($command, $body) = $handler->extractCommand('what about !reject ?');
+    $this->assertEqual(DifferentialAction::ACTION_COMMENT, $command);
+    $this->assertEqual('what about !reject ?', $body);
+
+    list($command, $body) = $handler->extractCommand(" !reject\nso awesome");
+    $this->assertEqual('reject', $command);
+    $this->assertEqual('so awesome', $body);
+  }
+}