diff --git a/lib/ansible/runner/__init__.py b/lib/ansible/runner/__init__.py
index c2dc875caf..f06012137e 100644
--- a/lib/ansible/runner/__init__.py
+++ b/lib/ansible/runner/__init__.py
@@ -343,7 +343,7 @@ class Runner(object):
             if type(items) != list:
                 raise errors.AnsibleError("lookup plugins have to return a list: %r" % items)
 
-            if len(items) and self.module_name in [ 'apt', 'yum' ]:
+            if len(items) and utils.is_list_of_strings(items) and self.module_name in [ 'apt', 'yum' ]:
                 # hack for apt and soon yum, with_items maps back into a single module call
                 inject['item'] = ",".join(items)
                 items = None
diff --git a/lib/ansible/utils/__init__.py b/lib/ansible/utils/__init__.py
index 466fbb3f95..40d42ba146 100644
--- a/lib/ansible/utils/__init__.py
+++ b/lib/ansible/utils/__init__.py
@@ -654,4 +654,9 @@ def get_diff(diff):
     except UnicodeDecodeError:
         return ">> the files are different, but the diff library cannot compare unicode strings"
 
- 
+def is_list_of_strings(items):
+   for x in items: 
+       if not isinstance(x, basestring):
+           return False
+   return True
+