diff --git a/docs/c-api/coap.h/mg_coap_add_option.md b/docs/c-api/coap.h/mg_coap_add_option.md
index 5867b7b78e12647c25313c3cb041d7ff14e12d0b..83e91d5f3af8f3a7b3eeac0457cf62bf09776e66 100644
--- a/docs/c-api/coap.h/mg_coap_add_option.md
+++ b/docs/c-api/coap.h/mg_coap_add_option.md
@@ -9,5 +9,6 @@ signature: |
 ---
 
 Adds a new option to mg_coap_message structure.
-Returns pointer to the newly created option. 
+Returns pointer to the newly created option.
+Note: options must be freed by using mg_coap_free_options 
 
diff --git a/mongoose.h b/mongoose.h
index f4b2ca51bb9cf606db886bb70167e681f90245cc..265b075b129f84ceb59c54f35a8f8b2e7f0e7f23 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -5328,6 +5328,7 @@ int mg_set_protocol_coap(struct mg_connection *nc);
 /*
  * Adds a new option to mg_coap_message structure.
  * Returns pointer to the newly created option.
+ * Note: options must be freed by using mg_coap_free_options
  */
 struct mg_coap_option *mg_coap_add_option(struct mg_coap_message *cm,
                                           uint32_t number, char *value,