diff --git a/src/include/lwip/api.h b/src/include/lwip/api.h
index 4975d490..c24db85a 100644
--- a/src/include/lwip/api.h
+++ b/src/include/lwip/api.h
@@ -1,6 +1,6 @@
 /**
  * @file
- * netconn API
+ * netconn API (to be used from non-TCPIP threads)
  */
 
 /*