diff --git a/commerce/interfaces.py b/commerce/interfaces.py
index 8ced6c9..802b071 100644
--- a/commerce/interfaces.py
+++ b/commerce/interfaces.py
@@ -1,6 +1,6 @@
 #-*- coding: UTF-8 -*-
 #
-#  Copyright (c) 2012 Helmut Merz helmutm@cy55.de
+#  Copyright (c) 2015 Helmut Merz helmutm@cy55.de
 #
 #  This program is free software; you can redistribute it and/or modify
 #  it under the terms of the GNU General Public License as published by
@@ -408,12 +408,13 @@ class IOrderItem(ITrack):
     shop = Attribute(u'The shop from which the product is ordered.')
     order = Attribute(u'The order this order item belongs to.')
     unitPrice = Attribute(u'The basic unit price for one of the product '
-                    u'items ordered.')
+                    u'ites ordered.')
     fullPrice = Attribute(u'The full price for the quantity ordered.')
     quantityShipped = Attribute(u'The total quantity that has been shipped '
                     u'already.')
     shippingInfo = Attribute(u'A list of mappings, with fields like: '
                     u'shippingId, shippingDate, quantity, packageId')
+    options = Attribute(u'Product options associated with this order item.')
 
     def remove():
         """ Remove the order item from the order or cart.
diff --git a/commerce/order.py b/commerce/order.py
index 66732e7..1c66618 100644
--- a/commerce/order.py
+++ b/commerce/order.py
@@ -1,5 +1,5 @@
 #
-#  Copyright (c) 2009 Helmut Merz helmutm@cy55.de
+#  Copyright (c) 2015 Helmut Merz helmutm@cy55.de
 #
 #  This program is free software; you can redistribute it and/or modify
 #  it under the terms of the GNU General Public License as published by
@@ -18,8 +18,6 @@
 
 """
 Order and order item classes.
-
-$Id$
 """
 
 from zope.app.intid.interfaces import IIntIds
@@ -118,7 +116,10 @@ class OrderItems(object):
 
     def add(self, product, party, shop, order='???', run=0, **kw):
         kw['shop'] = self.getUid(shop)
+        options = kw.get('options', [])
         existing = self.getCart(party, order, shop, run, product=product)
+        existing = [item for item in existing 
+                         if (item.data.get('options') or []) == options]
         if existing:
             track = existing[-1]
             track.modify(track.quantity + kw.get('quantity', 1))