diff --git a/vector/src/main/java/im/vector/riotx/core/dialogs/Extensions.kt b/vector/src/main/java/im/vector/riotx/core/dialogs/Extensions.kt
new file mode 100644
index 0000000000..1b90e88864
--- /dev/null
+++ b/vector/src/main/java/im/vector/riotx/core/dialogs/Extensions.kt
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2019 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package im.vector.riotx.core.dialogs
+
+import androidx.annotation.ColorRes
+import androidx.appcompat.app.AlertDialog
+import androidx.core.content.ContextCompat
+import im.vector.riotx.R
+
+fun AlertDialog.withColoredButton(whichButton: Int, @ColorRes color: Int = R.color.vector_error_color): AlertDialog {
+    getButton(whichButton)?.setTextColor(ContextCompat.getColor(context, color))
+    return this
+}
diff --git a/vector/src/main/java/im/vector/riotx/features/home/room/detail/RoomDetailFragment.kt b/vector/src/main/java/im/vector/riotx/features/home/room/detail/RoomDetailFragment.kt
index 264c0e98bc..4149436166 100644
--- a/vector/src/main/java/im/vector/riotx/features/home/room/detail/RoomDetailFragment.kt
+++ b/vector/src/main/java/im/vector/riotx/features/home/room/detail/RoomDetailFragment.kt
@@ -19,6 +19,7 @@ package im.vector.riotx.features.home.room.detail
 import android.annotation.SuppressLint
 import android.app.Activity.RESULT_OK
 import android.content.Context
+import android.content.DialogInterface
 import android.content.Intent
 import android.graphics.drawable.ColorDrawable
 import android.net.Uri
@@ -69,6 +70,7 @@ import im.vector.matrix.android.api.session.room.timeline.getLastMessageContent
 import im.vector.matrix.android.api.session.user.model.User
 import im.vector.riotx.R
 import im.vector.riotx.core.di.ScreenComponent
+import im.vector.riotx.core.dialogs.withColoredButton
 import im.vector.riotx.core.epoxy.LayoutManagerStateRestorer
 import im.vector.riotx.core.error.ErrorFormatter
 import im.vector.riotx.core.extensions.hideKeyboard
@@ -819,6 +821,7 @@ class RoomDetailFragment :
                                         .setPositiveButton(R.string.ok, null)
                                         .setNegativeButton(R.string.block_user) { _, _ -> vectorBaseActivity.notImplemented("block user") }
                                         .show()
+                                        .withColoredButton(DialogInterface.BUTTON_NEGATIVE)
                             }
                             data.inappropriate -> {
                                 AlertDialog.Builder(requireActivity())
@@ -827,6 +830,7 @@ class RoomDetailFragment :
                                         .setPositiveButton(R.string.ok, null)
                                         .setNegativeButton(R.string.block_user) { _, _ -> vectorBaseActivity.notImplemented("block user") }
                                         .show()
+                                        .withColoredButton(DialogInterface.BUTTON_NEGATIVE)
                             }
                             else               -> {
                                 AlertDialog.Builder(requireActivity())
@@ -835,6 +839,7 @@ class RoomDetailFragment :
                                         .setPositiveButton(R.string.ok, null)
                                         .setNegativeButton(R.string.block_user) { _, _ -> vectorBaseActivity.notImplemented("block user") }
                                         .show()
+                                        .withColoredButton(DialogInterface.BUTTON_NEGATIVE)
                             }
                         }
                     }