To do an eval that's fairly safe, you could use an external method like def my_zope_eval(s,dict=None): '''evaluate *s* in *dict*.''' if dict is None: dict= {} dict['__builtins__']= None return eval(s,dict) This is an old solution due to Dieter. Note that there are still dangerous things that a malicious use could do with this. There are several alternatives. Using RestrictedPython may allow for other nice solutions. Greg