diff --git a/lib/loofah/concerns.rb b/lib/loofah/concerns.rb
index 9e0f5d7..383038f 100644
--- a/lib/loofah/concerns.rb
+++ b/lib/loofah/concerns.rb
@@ -123,10 +123,16 @@ def to_text(options = {})
   end
 
   module DocumentDecorator # :nodoc:
+    class << self
+      def decorate(object)
+        object.decorators(Nokogiri::XML::Node) << ScrubBehavior::Node
+        object.decorators(Nokogiri::XML::NodeSet) << ScrubBehavior::NodeSet
+      end
+    end
+
     def initialize(*args, &block)
       super
-      decorators(Nokogiri::XML::Node) << ScrubBehavior::Node
-      decorators(Nokogiri::XML::NodeSet) << ScrubBehavior::NodeSet
+      DocumentDecorator.decorate(self)
     end
   end
 
diff --git a/lib/loofah/html4/document.rb b/lib/loofah/html4/document.rb
index 593380b..6e87934 100644
--- a/lib/loofah/html4/document.rb
+++ b/lib/loofah/html4/document.rb
@@ -12,6 +12,16 @@ class Document < Nokogiri::HTML4::Document
       include Loofah::DocumentDecorator
       include Loofah::TextBehavior
       include Loofah::HtmlDocumentBehavior
+
+      module NokogiriExtender
+        def acts_as_loofah
+          super
+          singleton_class.include(Loofah::TextBehavior)
+          singleton_class.include(Loofah::HtmlDocumentBehavior)
+        end
+      end
     end
   end
 end
+
+Nokogiri::HTML4::Document.include(Loofah::HTML4::Document::NokogiriExtender)
diff --git a/lib/loofah/html4/document_fragment.rb b/lib/loofah/html4/document_fragment.rb
index 988f4b9..63e7f69 100644
--- a/lib/loofah/html4/document_fragment.rb
+++ b/lib/loofah/html4/document_fragment.rb
@@ -10,6 +10,16 @@ module HTML4 # :nodoc:
     class DocumentFragment < Nokogiri::HTML4::DocumentFragment
       include Loofah::TextBehavior
       include Loofah::HtmlFragmentBehavior
+
+      module NokogiriExtender
+        def acts_as_loofah
+          super
+          singleton_class.include(Loofah::TextBehavior)
+          singleton_class.include(Loofah::HtmlFragmentBehavior)
+        end
+      end
     end
   end
 end
+
+Nokogiri::HTML4::DocumentFragment.include(Loofah::HTML4::DocumentFragment::NokogiriExtender)
diff --git a/lib/loofah/xml/document.rb b/lib/loofah/xml/document.rb
index cbdc804..f38f807 100644
--- a/lib/loofah/xml/document.rb
+++ b/lib/loofah/xml/document.rb
@@ -5,11 +5,32 @@ module XML # :nodoc:
     #
     #  Subclass of Nokogiri::XML::Document.
     #
-    #  See Loofah::ScrubBehavior and Loofah::DocumentDecorator for additional methods.
+    #  See Loofah::ScrubBehavior for additional methods.
     #
     class Document < Nokogiri::XML::Document
       include Loofah::ScrubBehavior::Node
       include Loofah::DocumentDecorator
+
+      module NokogiriExtender
+        def acts_as_loofah
+          singleton_class.include(Loofah::ScrubBehavior::Node)
+          Loofah::DocumentDecorator.decorate(self)
+          decorate_existing
+        end
+
+        # TODO: this should to be upstreamed into Nokogiri
+        def decorate_existing # :nodoc:
+          return unless @decorators
+
+          if Nokogiri.jruby?
+            traverse { |node| decorate(node) }
+          else
+            @node_cache.each { |node| decorate(node) }
+          end
+        end
+      end
     end
   end
 end
+
+Nokogiri::XML::Document.include(Loofah::XML::Document::NokogiriExtender)
diff --git a/lib/loofah/xml/document_fragment.rb b/lib/loofah/xml/document_fragment.rb
index aecf65a..df22d81 100644
--- a/lib/loofah/xml/document_fragment.rb
+++ b/lib/loofah/xml/document_fragment.rb
@@ -15,6 +15,23 @@ def parse(tags)
           new(doc, tags)
         end
       end
+
+      module NokogiriExtender
+        def acts_as_loofah
+          document.acts_as_loofah
+          decorate_existing
+        end
+
+        # TODO: this should to be upstreamed into Nokogiri
+        def decorate_existing # :nodoc:
+          return unless Nokogiri.jruby?
+          return unless document.instance_variable_get(:@decorators)
+
+          traverse { |node| document.decorate(node) }
+        end
+      end
     end
   end
 end
+
+Nokogiri::XML::DocumentFragment.include(Loofah::XML::DocumentFragment::NokogiriExtender)
diff --git a/test/unit/test_acts_as_loofah.rb b/test/unit/test_acts_as_loofah.rb
new file mode 100644
index 0000000..fd18cca
--- /dev/null
+++ b/test/unit/test_acts_as_loofah.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+require "helper"
+
+class UnitTestActsAsLoofah < Loofah::TestCase
+  SUBJECTS = [Nokogiri::XML, Nokogiri::HTML4, defined?(Nokogiri::HTML5) && Nokogiri::HTML5].compact
+
+  SUBJECTS.each do |subject|
+    describe subject do
+      it "Document act like Loofah" do
+        ndoc = subject::Document.parse("<html><body><div>hello</div><span>hello</span><script>alert(1)</script></body></html>")
+        node = ndoc.at_css("div")
+
+        # method presence
+        refute_respond_to(ndoc, :scrub!)
+        refute_respond_to(node, :scrub!)
+
+        ndoc.acts_as_loofah
+
+        assert_respond_to(ndoc, :scrub!, "#{subject}::Document should be extended")
+        assert_respond_to(ndoc.at_css("span"), :scrub!, "New child elements should be extended")
+        assert_respond_to(node, :scrub!, "Existing child elements should be extended")
+
+        refute_respond_to(subject::Document.parse("<div>"), :scrub!, "Other instances should not be extended")
+
+        # scrub behavior
+        ndoc.scrub!(:prune)
+
+        refute_includes(ndoc.to_html, "script")
+
+        # other concerns
+        if subject.name.include?("HTML")
+          assert_includes(ndoc.singleton_class.ancestors, Loofah::TextBehavior)
+          assert_includes(ndoc.singleton_class.ancestors, Loofah::HtmlDocumentBehavior)
+        end
+      end
+
+      it "DocumentFragment act like Loofah" do
+        nfrag = subject::DocumentFragment.parse("<div>hello</div><span>hello</span><script>alert(1)</script>")
+        node = nfrag.at_css("div")
+
+        # method presence
+        refute_respond_to(nfrag, :scrub!)
+        refute_respond_to(node, :scrub!)
+
+        nfrag.acts_as_loofah
+
+        assert_respond_to(nfrag, :scrub!, "#{subject}::DocumentFragment should be extended")
+        assert_respond_to(nfrag.at_css("span"), :scrub!, "New child elements should be extended")
+        assert_respond_to(node, :scrub!, "Existing child elements should be extended")
+
+        refute_respond_to(subject::DocumentFragment.parse("<div>"), :scrub!, "Other instances should not be extended")
+
+        # scrub behavior
+        nfrag.scrub!(:prune)
+
+        refute_includes(nfrag.to_html, "script")
+
+        # other concerns
+        if subject.name.include?("HTML")
+          assert_includes(nfrag.singleton_class.ancestors, Loofah::TextBehavior)
+          assert_includes(nfrag.singleton_class.ancestors, Loofah::HtmlFragmentBehavior)
+        end
+      end
+    end
+  end
+end