diff --git a/include/mbedtls/ccm.h b/include/mbedtls/ccm.h
index f89ddc2..c4fc6b5 100644
--- a/include/mbedtls/ccm.h
+++ b/include/mbedtls/ccm.h
@@ -297,6 +297,11 @@
  * \brief           This function starts a CCM encryption or decryption
  *                  operation.
  *
+ *                  This function and mbedtls_ccm_set_lengths() must be called
+ *                  before calling mbedtls_ccm_update_ad() or
+ *                  mbedtls_ccm_update(). This function can be called before
+ *                  or after mbedtls_ccm_set_lengths().
+ *
  * \note            This function is not implemented in Mbed TLS yet.
  *
  * \param ctx       The CCM context. This must be initialized.
@@ -325,6 +330,11 @@
  *                  and additional data for a CCM encryption or decryption
  *                  operation.
  *
+ *                  This function and mbedtls_ccm_starts() must be called
+ *                  before calling mbedtls_ccm_update_ad() or
+ *                  mbedtls_ccm_update(). This function can be called before
+ *                  or after mbedtls_ccm_starts().
+ *
  * \note            This function is not implemented in Mbed TLS yet.
  *
  * \param ctx       The CCM context. This must be initialized.