diff --git a/include/mbedtls/poly1305.h b/include/mbedtls/poly1305.h
index c490cdf..b02f968 100644
--- a/include/mbedtls/poly1305.h
+++ b/include/mbedtls/poly1305.h
@@ -43,7 +43,13 @@
 #include <stddef.h>
 
 #define MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA         -0x0057 /**< Invalid input parameter(s). */
+
+/* MBEDTLS_ERR_POLY1305_FEATURE_UNAVAILABLE is deprecated and should not be
+ * used. */
 #define MBEDTLS_ERR_POLY1305_FEATURE_UNAVAILABLE    -0x0059 /**< Feature not available. For example, s part of the API is not implemented. */
+
+/* MBEDTLS_ERR_POLY1305_HW_ACCEL_FAILED is deprecated and should not be used.
+ */
 #define MBEDTLS_ERR_POLY1305_HW_ACCEL_FAILED        -0x005B  /**< Poly1305 hardware accelerator failed. */
 
 #ifdef __cplusplus