diff --git a/quic/core/http/http_frames.h b/quic/core/http/http_frames.h
index 319e42b..87c574b 100644
--- a/quic/core/http/http_frames.h
+++ b/quic/core/http/http_frames.h
@@ -15,7 +15,6 @@
 #include "absl/strings/string_view.h"
 #include "net/third_party/quiche/src/quic/core/http/spdy_utils.h"
 #include "net/third_party/quiche/src/quic/core/quic_types.h"
-#include "net/third_party/quiche/src/quic/platform/api/quic_string_utils.h"
 #include "net/third_party/quiche/src/spdy/core/spdy_framer.h"
 
 namespace quic {
@@ -88,7 +87,7 @@
           SpdyUtils::H3SettingsToString(
               static_cast<Http3AndQpackSettingsIdentifiers>(it.first)),
           " = ", it.second, "; ");
-      QuicStrAppend(&s, setting);
+      absl::StrAppend(&s, setting);
     }
     return s;
   }
diff --git a/quic/core/qpack/qpack_instruction_encoder.cc b/quic/core/qpack/qpack_instruction_encoder.cc
index d114ece..2b9a1eb 100644
--- a/quic/core/qpack/qpack_instruction_encoder.cc
+++ b/quic/core/qpack/qpack_instruction_encoder.cc
@@ -6,12 +6,12 @@
 
 #include <limits>
 
+#include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "net/third_party/quiche/src/http2/hpack/huffman/hpack_huffman_encoder.h"
 #include "net/third_party/quiche/src/http2/hpack/varint/hpack_varint_encoder.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_flags.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_logging.h"
-#include "net/third_party/quiche/src/quic/platform/api/quic_string_utils.h"
 
 namespace quic {
 
@@ -167,7 +167,7 @@
   if (use_huffman_) {
     http2::HuffmanEncodeFast(string_to_write, string_length_, output);
   } else {
-    QuicStrAppend(output, string_to_write);
+    absl::StrAppend(output, string_to_write);
   }
 
   ++field_;
diff --git a/quic/core/quic_connection.cc b/quic/core/quic_connection.cc
index 7258d8c..8f1fd4b 100644
--- a/quic/core/quic_connection.cc
+++ b/quic/core/quic_connection.cc
@@ -44,7 +44,6 @@
 #include "net/third_party/quiche/src/quic/platform/api/quic_logging.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_map_util.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_socket_address.h"
-#include "net/third_party/quiche/src/quic/platform/api/quic_string_utils.h"
 #include "net/third_party/quiche/src/common/platform/api/quiche_text_utils.h"
 
 namespace quic {
@@ -839,7 +838,7 @@
   }
   std::string error_details = "Received public reset.";
   if (perspective_ == Perspective::IS_CLIENT && !packet.endpoint_id.empty()) {
-    QuicStrAppend(&error_details, " From ", packet.endpoint_id, ".");
+    absl::StrAppend(&error_details, " From ", packet.endpoint_id, ".");
   }
   QUIC_DLOG(INFO) << ENDPOINT << error_details;
   QUIC_CODE_COUNT(quic_tear_down_local_connection_on_public_reset);
diff --git a/quic/core/quic_packets.cc b/quic/core/quic_packets.cc
index e4bf322..40202e6 100644
--- a/quic/core/quic_packets.cc
+++ b/quic/core/quic_packets.cc
@@ -15,7 +15,6 @@
 #include "net/third_party/quiche/src/quic/core/quic_versions.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_flag_utils.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_flags.h"
-#include "net/third_party/quiche/src/quic/platform/api/quic_string_utils.h"
 #include "net/third_party/quiche/src/common/platform/api/quiche_text_utils.h"
 
 namespace quic {
@@ -580,9 +579,9 @@
                    ", packet_length: ", packet.length(),
                    ", header_format: ", form, ", version_flag: ", version_flag);
   if (version_flag) {
-    QuicStrAppend(&output, ", version: ", ParsedQuicVersionToString(version));
+    absl::StrAppend(&output, ", version: ", ParsedQuicVersionToString(version));
   }
-  QuicStrAppend(
+  absl::StrAppend(
       &output,
       ", destination_connection_id: ", destination_connection_id.ToString(),
       ", source_connection_id: ", source_connection_id.ToString(), " }\n");