diff --git a/lib/adapters/http.js b/lib/adapters/http.js
index 87b389c351..7541983975 100755
--- a/lib/adapters/http.js
+++ b/lib/adapters/http.js
@@ -300,9 +300,11 @@ module.exports = function httpAdapter(config) {
       // ClientRequest.setTimeout will be fired on the specify milliseconds, and can make sure that abort() will be fired after connect.
       req.setTimeout(timeout, function handleRequestTimeout() {
         req.abort();
-        var timeoutErrorMessage = 'timeout of ' + config.timeout + 'ms exceeded';
+        var timeoutErrorMessage = '';
         if (config.timeoutErrorMessage) {
           timeoutErrorMessage = config.timeoutErrorMessage;
+        } else {
+          timeoutErrorMessage = 'timeout of ' + config.timeout + 'ms exceeded';
         }
         reject(createError(timeoutErrorMessage, config, 'ECONNABORTED', req));
       });