diff --git a/.changeset/nice-falcons-flash.md b/.changeset/nice-falcons-flash.md
new file mode 100644
index 000000000000..7731f18a6a83
--- /dev/null
+++ b/.changeset/nice-falcons-flash.md
@@ -0,0 +1,6 @@
+---
+'astro': patch
+'@astrojs/mdx': patch
+---
+
+Fix [Object AsyncGenerator] appearing in markup for Markdoc documents
diff --git a/packages/astro/src/runtime/server/render/astro/instance.ts b/packages/astro/src/runtime/server/render/astro/instance.ts
index abfcd94e89eb..ed5044575ae5 100644
--- a/packages/astro/src/runtime/server/render/astro/instance.ts
+++ b/packages/astro/src/runtime/server/render/astro/instance.ts
@@ -50,9 +50,6 @@ export class AstroComponentInstance {
 			value = await value;
 		}
 		if (isHeadAndContent(value)) {
-			if (this.result.extraHead.length === 0 && value.head) {
-				yield renderChild(value.head);
-			}
 			yield* value.content;
 		} else {
 			yield* renderChild(value);
diff --git a/packages/integrations/mdx/test/astro-content-css.test.js b/packages/integrations/mdx/test/astro-content-css.test.js
deleted file mode 100644
index 712aaf54771b..000000000000
--- a/packages/integrations/mdx/test/astro-content-css.test.js
+++ /dev/null
@@ -1,49 +0,0 @@
-import { expect } from 'chai';
-import * as cheerio from 'cheerio';
-import { loadFixture } from '../../../astro/test/test-utils.js';
-import mdx from '@astrojs/mdx';
-
-describe('build css from the component', async () => {
-	let fixture;
-
-	before(async () => {
-		fixture = await loadFixture({
-			root: new URL('./fixtures/astro-content-css/', import.meta.url),
-			integrations: [mdx()],
-		});
-		await fixture.build();
-	});
-
-	describe('Build', () => {
-		before(async () => {
-			await fixture.build();
-		});
-
-		it('including css and js from the component in pro', async () => {
-			const html = await fixture.readFile('/index.html');
-			const $ = cheerio.load(html);
-			expect($('link[href$=".css"]').attr('href')).to.match(/^\/_astro\//);
-			expect($('script[src$=".js"]').attr('src')).to.match(/^\/_astro\//);
-		});
-	});
-
-	describe('Dev', () => {
-		let devServer;
-		before(async () => {
-			devServer = await fixture.startDevServer();
-		});
-
-		after(async () => {
-			devServer.stop();
-		});
-
-		it('ncluding css and js from the component in Dev', async () => {
-			let res = await fixture.fetch(`/`);
-			expect(res.status).to.equal(200);
-			const html = await res.text();
-			const $ = cheerio.load(html);
-			expect($.html()).to.include('CornflowerBlue');
-			expect($('script[src$=".js"]').attr('src')).to.include('astro');
-		});
-	});
-});
diff --git a/packages/integrations/mdx/test/fixtures/astro-content-css/astro.config.mjs b/packages/integrations/mdx/test/fixtures/astro-content-css/astro.config.mjs
deleted file mode 100644
index b67da09a917e..000000000000
--- a/packages/integrations/mdx/test/fixtures/astro-content-css/astro.config.mjs
+++ /dev/null
@@ -1,11 +0,0 @@
-import { defineConfig } from 'astro/config';
-
-import mdx from "@astrojs/mdx";
-
-// https://astro.build/config
-export default defineConfig({
-  build: {
-    format: 'file'
-  },
-  integrations: [mdx()]
-});
diff --git a/packages/integrations/mdx/test/fixtures/astro-content-css/package.json b/packages/integrations/mdx/test/fixtures/astro-content-css/package.json
deleted file mode 100644
index 8d436998c640..000000000000
--- a/packages/integrations/mdx/test/fixtures/astro-content-css/package.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "name": "@test/astro-content-css",
-  "version": "0.0.0",
-  "private": true,
-  "dependencies": {
-    "astro": "workspace:*",
-    "@astrojs/mdx": "workspace:*"
-  }
-}
diff --git a/packages/integrations/mdx/test/fixtures/astro-content-css/src/content/config.ts b/packages/integrations/mdx/test/fixtures/astro-content-css/src/content/config.ts
deleted file mode 100644
index bf1a34c0528f..000000000000
--- a/packages/integrations/mdx/test/fixtures/astro-content-css/src/content/config.ts
+++ /dev/null
@@ -1,12 +0,0 @@
-// 1. Import utilities from `astro:content`
-import { z, defineCollection } from 'astro:content';
-// 2. Define a schema for each collection you'd like to validate.
-const dynamicCollection = defineCollection({
-  schema: z.object({
-    title: z.string(),
-  }),
-});
-// 3. Export a single `collections` object to register your collection(s)
-export const collections = {
-  dynamic: dynamicCollection,
-};
diff --git a/packages/integrations/mdx/test/fixtures/astro-content-css/src/content/dynamic/FirstComponentWithJS.astro b/packages/integrations/mdx/test/fixtures/astro-content-css/src/content/dynamic/FirstComponentWithJS.astro
deleted file mode 100644
index f3b588b42713..000000000000
--- a/packages/integrations/mdx/test/fixtures/astro-content-css/src/content/dynamic/FirstComponentWithJS.astro
+++ /dev/null
@@ -1,18 +0,0 @@
----
-const { text } = Astro.props;
----
-<!DOCTYPE html>
-<html lang="en">
-	<head><meta charset="utf-8" /></head>
-	<body>
-    <div id="first">1st components with js. Props: {text}. <span>Styles</span>. JS: </div>
-	</body>
-</html>
-<script>
-  document.querySelector('#first').innerHTML += 'works';
-</script>
-<style>
-  #first > span {
-    color: CornflowerBlue;
-  }
-</style>
\ No newline at end of file
diff --git a/packages/integrations/mdx/test/fixtures/astro-content-css/src/content/dynamic/first-component-with-js.mdx b/packages/integrations/mdx/test/fixtures/astro-content-css/src/content/dynamic/first-component-with-js.mdx
deleted file mode 100644
index 0abdfbe3a4f8..000000000000
--- a/packages/integrations/mdx/test/fixtures/astro-content-css/src/content/dynamic/first-component-with-js.mdx
+++ /dev/null
@@ -1,9 +0,0 @@
----
-title: 'First component'
----
-
-import FirstDynamicComponentWithJS from './FirstComponentWithJS.astro';
-
-<FirstDynamicComponentWithJS text={props.mdProps} />
-
-Additional text from mdx 'first-component-with-js'
diff --git a/packages/integrations/mdx/test/fixtures/astro-content-css/src/pages/index.astro b/packages/integrations/mdx/test/fixtures/astro-content-css/src/pages/index.astro
deleted file mode 100644
index 63ea9ddbb41b..000000000000
--- a/packages/integrations/mdx/test/fixtures/astro-content-css/src/pages/index.astro
+++ /dev/null
@@ -1,16 +0,0 @@
----
-import { getCollection } from 'astro:content';
-
-const entries = await getCollection('dynamic');
----
-
-<!DOCTYPE html>
-<html lang="en">
-  <head><meta charset="utf-8" /></head>
-	<body>
-		{entries.map(async entry => {
-			const { Content } = await entry.render();
-			return <Content mdProps="work" />; 
-		})}
-	</body>
-</html>
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 29d4f497a347..63bb9e6f09b9 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -4259,15 +4259,6 @@ importers:
         specifier: ^4.3.1
         version: 4.3.1(@types/node@18.16.3)(sass@1.52.2)
 
-  packages/integrations/mdx/test/fixtures/astro-content-css:
-    dependencies:
-      '@astrojs/mdx':
-        specifier: workspace:*
-        version: link:../../..
-      astro:
-        specifier: workspace:*
-        version: link:../../../../../astro
-
   packages/integrations/mdx/test/fixtures/css-head-mdx:
     dependencies:
       '@astrojs/mdx':