diff --git a/src/Fetch/MIME.php b/src/Fetch/MIME.php
index b63d72b..9ddbb4a 100644
--- a/src/Fetch/MIME.php
+++ b/src/Fetch/MIME.php
@@ -36,8 +36,14 @@ public static function decode($text, $targetCharset = 'utf-8')
 
         foreach (imap_mime_header_decode($text) as $word) {
             $ch = 'default' === $word->charset ? 'ascii' : $word->charset;
+            $text = $word->text;
+            if (function_exists('mb_convert_encoding')) {
+                // This will strip any unrecognised characters and ensure we avoid
+                // "Detected an incomplete multibyte character in input string" errors
+                $text = mb_convert_encoding($text, $ch, $ch);
+            }
 
-            $result .= iconv($ch, $targetCharset, $word->text);
+            $result .= iconv($ch, $targetCharset, $text);
         }
 
         return $result;