Once i had faced problem in one table which have more than 287 duplicate constraints.
So i had buid one solution as below.
I had create one script and saved in c:\ REMOVECONSTRAINT.sql.
Contains of the script REMOVECONSTRAINT.sql as below.
SET HEADING OFF
select 'alter table 'OWNER'.'table_name' drop constraint 'constraint_name' cascade;'
from dba_constraints where owner=UPPER('&owner') and table_name=UPPER('&table_name')
if you go through with script you come to know it will generate dropconstraint.sql and execute it.
This script will remove all constraint from table.
After this you need to Re-create constraints your constraints.