diff --git a/benchmark/mime/parse-type-and-subtype.js b/benchmark/mime/parse-type-and-subtype.js
deleted file mode 100644
index 4b91dc1db6a..00000000000
--- a/benchmark/mime/parse-type-and-subtype.js
+++ /dev/null
@@ -1,53 +0,0 @@
-'use strict';
-
-const common = require('../common');
-const assert = require('assert');
-
-const bench = common.createBenchmark(main, {
-  n: [1e7],
-  value: [
-    'application/ecmascript; ',
-    'text/html;charset=gbk',
-    // eslint-disable-next-line max-len
-    'text/html;0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789=x;charset=gbk',
-  ],
-}, {
-  flags: ['--expose-internals'],
-});
-
-function main({ n, value }) {
-
-  const parseTypeAndSubtype = require('internal/mime').parseTypeAndSubtype;
-  // Warm up.
-  const length = 1024;
-  const array = [];
-  let errCase = false;
-
-  for (let i = 0; i < length; ++i) {
-    try {
-      array.push(parseTypeAndSubtype(value));
-    } catch (e) {
-      errCase = true;
-      array.push(e);
-    }
-  }
-
-  // console.log(`errCase: ${errCase}`);
-  bench.start();
-  for (let i = 0; i < n; ++i) {
-    const index = i % length;
-    try {
-      array[index] = parseTypeAndSubtype(value);
-    } catch (e) {
-      array[index] = e;
-    }
-  }
-
-  bench.end(n);
-
-  // Verify the entries to prevent dead code elimination from making
-  // the benchmark invalid.
-  for (let i = 0; i < length; ++i) {
-    assert.strictEqual(typeof array[i], errCase ? 'object' : 'object');
-  }
-}
diff --git a/benchmark/mime/to-ascii-lower.js b/benchmark/mime/to-ascii-lower.js
deleted file mode 100644
index 93a4a14dc6d..00000000000
--- a/benchmark/mime/to-ascii-lower.js
+++ /dev/null
@@ -1,54 +0,0 @@
-'use strict';
-
-const common = require('../common');
-const assert = require('assert');
-
-const bench = common.createBenchmark(main, {
-  n: [1e7],
-  value: [
-    'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
-    'UPPERCASE',
-    'lowercase',
-    'mixedCase',
-  ],
-}, {
-  flags: ['--expose-internals'],
-});
-
-function main({ n, value }) {
-
-  const toASCIILower = require('internal/mime').toASCIILower;
-  // Warm up.
-  const length = 1024;
-  const array = [];
-  let errCase = false;
-
-  for (let i = 0; i < length; ++i) {
-    try {
-      array.push(toASCIILower(value));
-    } catch (e) {
-      errCase = true;
-      array.push(e);
-    }
-  }
-
-  // console.log(`errCase: ${errCase}`);
-  bench.start();
-
-  for (let i = 0; i < n; ++i) {
-    const index = i % length;
-    try {
-      array[index] = toASCIILower(value);
-    } catch (e) {
-      array[index] = e;
-    }
-  }
-
-  bench.end(n);
-
-  // Verify the entries to prevent dead code elimination from making
-  // the benchmark invalid.
-  for (let i = 0; i < length; ++i) {
-    assert.strictEqual(typeof array[i], errCase ? 'object' : 'string');
-  }
-}
diff --git a/lib/internal/mime.js b/lib/internal/mime.js
index 332ed8b5368..0a1d8e7e679 100644
--- a/lib/internal/mime.js
+++ b/lib/internal/mime.js
@@ -384,8 +384,6 @@ ObjectDefineProperty(MIMEType.prototype, 'toJSON', {
 });
 
 module.exports = {
-  toASCIILower,
-  parseTypeAndSubtype,
   MIMEParams,
   MIMEType,
 };
diff --git a/test/parallel/test-mime-api.js b/test/parallel/test-mime-api.js
index 0fabd1a4cce..30272e5aa64 100644
--- a/test/parallel/test-mime-api.js
+++ b/test/parallel/test-mime-api.js
@@ -4,8 +4,6 @@
 require('../common');
 const assert = require('assert');
 const { MIMEType, MIMEParams } = require('util');
-const { toASCIILower } = require('internal/mime');
-
 
 const WHITESPACES = '\t\n\f\r ';
 const NOT_HTTP_TOKEN_CODE_POINT = ',';
@@ -160,8 +158,3 @@ assert.throws(() => params.set(`x${NOT_HTTP_TOKEN_CODE_POINT}`, 'x'), /parameter
 assert.throws(() => params.set('x', `${NOT_HTTP_QUOTED_STRING_CODE_POINT};`), /parameter value/i);
 assert.throws(() => params.set('x', `${NOT_HTTP_QUOTED_STRING_CODE_POINT}x`), /parameter value/i);
 assert.throws(() => params.set('x', `x${NOT_HTTP_QUOTED_STRING_CODE_POINT}`), /parameter value/i);
-
-assert.strictEqual(toASCIILower('someThing'), 'something');
-assert.strictEqual(toASCIILower('SomeThing'), 'something');
-assert.strictEqual(toASCIILower('SomeThing3'), 'something3');
-assert.strictEqual(toASCIILower('ABCDEFGHIJKLMNOPQRSTUVWXYZ'), 'abcdefghijklmnopqrstuvwxyz');