diff --git a/src/HL7/Message.php b/src/HL7/Message.php
index 95574df..660a77a 100644
--- a/src/HL7/Message.php
+++ b/src/HL7/Message.php
@@ -73,7 +73,9 @@ public function __construct(string $msgStr = null, array $hl7Globals = null, boo
             $segments = preg_split("/[\n\r" . $this->segmentSeparator . ']/', $msgStr, -1, PREG_SPLIT_NO_EMPTY);
 
             // The first segment should be the control segment
-            preg_match('/^([A-Z0-9]{3})(.)(.)(.)(.)(.)(.)/', $segments[0], $matches);
+            if (!preg_match('/^([A-Z0-9]{3})(.)(.)(.)(.)(.)(.)/', $segments[0], $matches)) {
+                throw new HL7Exception('Not a valid message: invalid control segment', E_USER_ERROR);
+            }
 
             [$dummy, $hdr, $fieldSep, $compSep, $repSep, $esc, $subCompSep, $fieldSepCtrl] = $matches;
 
diff --git a/tests/MessageTest.php b/tests/MessageTest.php
index aeaa286..b0dcfee 100644
--- a/tests/MessageTest.php
+++ b/tests/MessageTest.php
@@ -223,4 +223,14 @@ public function a_segment_can_be_retrieved_as_a_string()
         $this->assertSame('1', $msg->getSegmentFieldAsString(0, 3), 'MSH(3) as string');
         $this->assertSame('a^b1&b2^c', $msg->getSegmentFieldAsString(1, 2), 'XXX(2) as string');
     }
+
+    /**
+     * @test
+     * @expectedException Aranyasen\Exceptions\HL7Exception
+     * @expectedExceptionMessage Not a valid message: invalid control segment
+     */
+    public function an_exception_will_be_throw_in_invalid_string()
+    {
+        $msg = new Message("I'm an invalid message");
+    }
 }