diff --git a/database/migrations/2026_10_28_124421_keep_dockerfile_healthcheck_for_existing_applications.php b/database/migrations/2026_10_28_124421_keep_dockerfile_healthcheck_for_existing_applications.php
new file mode 100644
index 0000000000..e9c3d8f13b
--- /dev/null
+++ b/database/migrations/2026_10_28_124421_keep_dockerfile_healthcheck_for_existing_applications.php
@@ -0,0 +1,25 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Support\Facades\DB;
+
+return new class extends Migration
+{
+    /**
+     * Until v4.5.0, a HEALTHCHECK in the Dockerfile was used even when the Coolify healthcheck was enabled.
+     * Since v4.5.1 an enabled Coolify healthcheck replaces it. Existing applications with a Dockerfile
+     * HEALTHCHECK get the Coolify healthcheck disabled, so their deployments keep the Dockerfile healthcheck.
+     */
+    public function up(): void
+    {
+        DB::table('applications')
+            ->where('custom_healthcheck_found', true)
+            ->where('health_check_enabled', true)
+            ->update(['health_check_enabled' => false]);
+    }
+
+    public function down(): void
+    {
+        // This data migration cannot identify which applications had the Coolify healthcheck enabled.
+    }
+};
diff --git a/resources/views/livewire/project/shared/health-checks.blade.php b/resources/views/livewire/project/shared/health-checks.blade.php
index 6b02c0bf31..0a0cba98d1 100644
--- a/resources/views/livewire/project/shared/health-checks.blade.php
+++ b/resources/views/livewire/project/shared/health-checks.blade.php
@@ -26,9 +26,16 @@
 
         @if ($customHealthcheckFound)
             <div class="mb-4">
-                <x-callout type="warning" title="Custom healthcheck detected">
-                    Enabling this configuration replaces the custom healthcheck currently defined by the application.
-                </x-callout>
+                @if ($healthCheckEnabled)
+                    <x-callout type="warning" title="Dockerfile HEALTHCHECK replaced">
+                        This healthcheck replaces the HEALTHCHECK from the Dockerfile. Disable it to use the
+                        Dockerfile HEALTHCHECK again.
+                    </x-callout>
+                @else
+                    <x-callout type="info" title="Dockerfile HEALTHCHECK in use">
+                        The application uses the HEALTHCHECK from its Dockerfile. Enabling this healthcheck replaces it.
+                    </x-callout>
+                @endif
             </div>
         @endif
 
diff --git a/tests/Feature/KeepDockerfileHealthcheckMigrationTest.php b/tests/Feature/KeepDockerfileHealthcheckMigrationTest.php
new file mode 100644
index 0000000000..d994272c16
--- /dev/null
+++ b/tests/Feature/KeepDockerfileHealthcheckMigrationTest.php
@@ -0,0 +1,69 @@
+<?php
+
+use App\Livewire\Project\Shared\HealthChecks;
+use App\Models\Application;
+use App\Models\InstanceSettings;
+use App\Models\Project;
+use App\Models\Server;
+use App\Models\StandaloneDocker;
+use App\Models\Team;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Livewire\Livewire;
+
+uses(RefreshDatabase::class);
+
+beforeEach(function () {
+    Server::flushIdentityMap();
+    InstanceSettings::forceCreate(['id' => 0]);
+
+    $team = Team::factory()->create();
+    $this->healthcheckMigrationOwner = User::factory()->create();
+    $team->members()->attach($this->healthcheckMigrationOwner->id, ['role' => 'owner']);
+    $project = Project::factory()->create(['team_id' => $team->id]);
+    $server = Server::factory()->create(['team_id' => $team->id]);
+    $this->healthcheckMigrationEnvironment = $project->environments()->firstOrFail();
+    $this->healthcheckMigrationDestination = StandaloneDocker::query()->where('server_id', $server->id)->firstOrFail();
+});
+
+function keepDockerfileHealthcheckApplication(bool $healthCheckEnabled, bool $customHealthcheckFound): Application
+{
+    return Application::factory()->create([
+        'environment_id' => test()->healthcheckMigrationEnvironment->id,
+        'destination_id' => test()->healthcheckMigrationDestination->id,
+        'destination_type' => StandaloneDocker::class,
+        'build_pack' => 'dockerfile',
+        'health_check_enabled' => $healthCheckEnabled,
+        'custom_healthcheck_found' => $customHealthcheckFound,
+    ])->fresh();
+}
+
+test('disables the Coolify healthcheck only for applications with a Dockerfile HEALTHCHECK', function () {
+    $dockerfileAndCoolify = keepDockerfileHealthcheckApplication(healthCheckEnabled: true, customHealthcheckFound: true);
+    $dockerfileOnly = keepDockerfileHealthcheckApplication(healthCheckEnabled: false, customHealthcheckFound: true);
+    $coolifyOnly = keepDockerfileHealthcheckApplication(healthCheckEnabled: true, customHealthcheckFound: false);
+    $none = keepDockerfileHealthcheckApplication(healthCheckEnabled: false, customHealthcheckFound: false);
+
+    (require database_path('migrations/2026_10_28_124421_keep_dockerfile_healthcheck_for_existing_applications.php'))->up();
+
+    expect($dockerfileAndCoolify->fresh()->health_check_enabled)->toBeFalse()
+        ->and($dockerfileAndCoolify->fresh()->custom_healthcheck_found)->toBeTrue()
+        ->and($dockerfileOnly->fresh()->health_check_enabled)->toBeFalse()
+        ->and($coolifyOnly->fresh()->health_check_enabled)->toBeTrue()
+        ->and($none->fresh()->health_check_enabled)->toBeFalse();
+});
+
+test('the healthcheck page says whether the Dockerfile HEALTHCHECK is in use or replaced', function () {
+    $this->actingAs($this->healthcheckMigrationOwner);
+
+    Livewire::test(HealthChecks::class, ['resource' => keepDockerfileHealthcheckApplication(healthCheckEnabled: false, customHealthcheckFound: true)])
+        ->assertSee('Dockerfile HEALTHCHECK in use')
+        ->assertDontSee('Dockerfile HEALTHCHECK replaced');
+
+    Livewire::test(HealthChecks::class, ['resource' => keepDockerfileHealthcheckApplication(healthCheckEnabled: true, customHealthcheckFound: true)])
+        ->assertSee('Dockerfile HEALTHCHECK replaced')
+        ->assertDontSee('Dockerfile HEALTHCHECK in use');
+
+    Livewire::test(HealthChecks::class, ['resource' => keepDockerfileHealthcheckApplication(healthCheckEnabled: true, customHealthcheckFound: false)])
+        ->assertDontSee('Dockerfile HEALTHCHECK');
+});