Epilepsy is a neurological disorder, which sometimes cannot be successfully treated. We propose a real-time closed-loop monitoring and controlling device for epileptic seizure detection and suppression. This wireless-networked embedded device includes signal conditioning circuitry, a stimulator, and a microcontroller with a wireless transceiver. A TI CC2430 receives the conditioned EEG signals and performs feature extraction on them to determine if a seizure has happened. The ZigBee-based wireless transceiver transmits the EEG data to the backend computer for future off-line study. If a seizure is detected after the real-time computation, an enabling signal is sent to the stimulator to generate stimulating pulses to suppress the seizure. The feature extraction is implemented using entropy and spectrum analysis, followed by an LLS classifier. A fast seizure detection response time of around 0.6 s and a seizure detection algorithm accuracy of above 95%, when applied to a standard dataset, were achieved with the proposed portable embedded device.