diff --git a/include/mbedtls/x509_crt.h b/include/mbedtls/x509_crt.h
index 938910c..bb6d376 100644
--- a/include/mbedtls/x509_crt.h
+++ b/include/mbedtls/x509_crt.h
@@ -279,7 +279,7 @@
  * \brief          Check usage of certificate against keyUsage extension.
  *
  * \param crt      Leaf certificate used.
- * \param usage    Intended usage(s) (eg MBEDTLS_KU_KEY_ENCIPHERMENT before using the
+ * \param usage    Intended usage(s) (eg MBEDTLS_X509_KU_KEY_ENCIPHERMENT before using the
  *                 certificate to perform an RSA key exchange).
  *
  * \return         0 is these uses of the certificate are allowed,