Divalproex delayed-release tablets are used for controlling certain types of seizures in the treatment of epilepsy. It is also used to treat the manic phase of bipolar disorders (manic-depressive illness) and to prevent migraine headaches. Divalproex delayed-release tablets are an anticonvulsant. It works by reducing or preventing the number of seizures by controlling the abnormal activity of nerve impulses in the brain and central nervous system. Exactly how it works to treat bipolar disorder and migraine headache is not known.