diff --git a/include/envoy/http/filter.h b/include/envoy/http/filter.h
index 4157dfc6819f7..f848fba08d8a4 100644
--- a/include/envoy/http/filter.h
+++ b/include/envoy/http/filter.h
@@ -591,6 +591,7 @@ class StreamDecoderFilter : public StreamFilterBase {
    * Called with a decoded data frame.
    * @param data supplies the decoded data.
    * @param end_stream supplies whether this is the last data frame.
+   * Further note that end_stream is only true if there are no trailers.
    * @return FilterDataStatus determines how filter chain iteration proceeds.
    */
   virtual FilterDataStatus decodeData(Buffer::Instance& data, bool end_stream) PURE;
@@ -825,6 +826,7 @@ class StreamEncoderFilter : public StreamFilterBase {
    * Called with data to be encoded, optionally indicating end of stream.
    * @param data supplies the data to be encoded.
    * @param end_stream supplies whether this is the last data frame.
+   * Further note that end_stream is only true if there are no trailers.
    * @return FilterDataStatus determines how filter chain iteration proceeds.
    */
   virtual FilterDataStatus encodeData(Buffer::Instance& data, bool end_stream) PURE;