Abstract-Our previous studies focused on channel simulation and performance evaluation of optical wireless links for medical body sensor networks. This allowed us to increase our expertise in this field and to propose here a full optical wireless bidirectional system named as LiFi communication system for medical monitoring applications. The full duplex bidirectional communication is based on an infrared uplink and visible downlink. The studied scenario considers a patient wearing both an infrared transmitter connected to a medical sensor and a visible light receiver. The infrared receivers and visible light emitters are included in light fixtures at the ceiling. The study relies on channel modelling considering patient body features, locations and movements. Using ray-tracing technique associated to MonteCarlo method, we determine the overall performance in terms of outage probability. We apply our methodology considering various medical sensors and show that it is possible to satisfy the overall quality of service in terms of bit error rate and data rate.