diff --git a/BUILD.gn b/BUILD.gn
index a0eda8f72e..5cef1303b2 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -711,8 +711,11 @@ if (rtc_include_tests) {
 group("poison_audio_codecs") {
 }
 
-group("poison_software_video_codecs") {
-}
-
 group("poison_default_task_queue") {
 }
+
+group("poison_rtc_json") {
+}
+
+group("poison_software_video_codecs") {
+}
diff --git a/api/audio/BUILD.gn b/api/audio/BUILD.gn
index bc6819050e..9ea145bc2c 100644
--- a/api/audio/BUILD.gn
+++ b/api/audio/BUILD.gn
@@ -52,6 +52,7 @@ rtc_library("aec3_config") {
 
 rtc_library("aec3_config_json") {
   visibility = [ "*" ]
+  allow_poison = [ "rtc_json" ]
   sources = [
     "echo_canceller3_config_json.cc",
     "echo_canceller3_config_json.h",
diff --git a/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index acd54b9839..0115429ae4 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -615,6 +615,7 @@ config("rtc_json_suppressions") {
 
 rtc_library("rtc_json") {
   public_configs = [ ":rtc_json_suppressions" ]
+  poisonous = [ "rtc_json" ]
   defines = []
   sources = [
     "strings/json.cc",
diff --git a/webrtc.gni b/webrtc.gni
index 603376435d..4e0f3641f2 100644
--- a/webrtc.gni
+++ b/webrtc.gni
@@ -366,11 +366,14 @@ all_poison_types = [
   # Encoders and decoders for specific audio codecs such as Opus and iSAC.
   "audio_codecs",
 
-  # Software video codecs (VP8 and VP9 through libvpx).
-  "software_video_codecs",
-
   # Default task queue implementation.
   "default_task_queue",
+
+  # JSON parsing should not be needed in the "slim and modular" WebRTC.
+  "rtc_json",
+
+  # Software video codecs (VP8 and VP9 through libvpx).
+  "software_video_codecs",
 ]
 
 absl_include_config = "//third_party/abseil-cpp:absl_include_config"