diff --git a/Modules/_csv.c b/Modules/_csv.c
index 89b0a0dce02..077416c4a16 100644
--- a/Modules/_csv.c
+++ b/Modules/_csv.c
@@ -1434,7 +1434,8 @@ PyDoc_STRVAR(csv_module_doc,
 "            field contains either the quotechar or the delimiter\n"
 "        csv.QUOTE_ALL means that quotes are always placed around fields.\n"
 "        csv.QUOTE_NONNUMERIC means that quotes are always placed around\n"
-"            fields which contain characters other than [+-0-9.].\n"
+"            fields which do not parse as integers or floating point\n"
+"            numbers.\n"
 "        csv.QUOTE_NONE means that quotes are never placed around fields.\n"
 "    * escapechar - specifies a one-character string used to escape \n"
 "        the delimiter when quoting is set to QUOTE_NONE.\n"