diff --git a/src/pip/_internal/commands/install.py b/src/pip/_internal/commands/install.py

index 1279d4a..aeb9d26 100644

--- a/src/pip/_internal/commands/install.py

+++ b/src/pip/_internal/commands/install.py

@@ -5,6 +5,8 @@ import logging

 import operator

 import os

 import shutil

+import sys

+from os import path

 from optparse import SUPPRESS_HELP

 from pip._vendor import pkg_resources

@@ -217,6 +219,23 @@ class InstallCommand(RequirementCommand):

     def run(self, options, args):

         cmdoptions.check_install_build_global(options)

+

+        def is_venv():

+            return (hasattr(sys, 'real_prefix') or

+                    (hasattr(sys, 'base_prefix') and

+                     sys.base_prefix != sys.prefix))

+

+        # Check whether we have root privileges and aren't in venv/virtualenv

+        if os.getuid() == 0 and not is_venv():

+            command = path.basename(sys.argv[0])

+            if command == "__main__.py":

+                command = path.basename(sys.executable) + " -m pip"

+            logger.warning(

+                "Running pip install with root privileges is "

+                "generally not a good idea. Try `%s install --user` instead."

+                % command

+            )

+

         upgrade_strategy = "to-satisfy-only"

         if options.upgrade:

             upgrade_strategy = options.upgrade_strategy