diff --git a/include/ucore/mbuf.h b/include/ucore/mbuf.h
index 723d575..3cf45cd 100644
--- a/include/ucore/mbuf.h
+++ b/include/ucore/mbuf.h
@@ -102,7 +102,8 @@ struct MBuf *uc_mbuf_new_inline_hr(uint32_t len, uint32_t headroom);
 void uc_mbuf_free(struct MBuf *mbuf);
 
 /** Create a new mbuf, with a copy of the data from the given
- * mbuf. The new mbuf will have the same headroom as the old one.
+ * mbuf. The new mbuf will have the same headroom as the old one,
+ * but no tailroom.
  *
  * @param mbuf mbuf to copy
  */