A microfluidic chip featuring laminar flow-based parallel gradient-generating networks was designed and fabricated. The microchip contains 5 gradient genera-tors and 30 cell chambers where the resulting concentra-tion gradients of drugs are delivered to stimulate on-chip cultured cells. The microfluidics exploits the advantage of lab-on-a-chip technology by integrating the generation of drug concentration gradients and a series of cell opera-tions including seeding, culture, stimulation and staining into a chip. The microfluidic network was patteed on a glass wafer, which was further bonded to a PDMS film. A series of weir structures were fabricated on the cell culture reservoir to facilitate cell positioning and seeding. Cell injection and fluid delivery were controlled by a syringe pump. Steady parallel concentration gradients were gen-erated by flowing two fluids in each network. Over time observation shows that the microchip was suitable for cell seeding and culture. The microchip described above was applied in studying the role of reduced glutathione (GSH) in mediating chemotherapy sensitivity of MCF-7 cells. MCF-7 cells were treated with concentration gradients of As2O3 and N-acetyl cysteine (NAC) for GSH modu-lation, followed by exposure to adriamycin. GSH levels were down-regulated upon As203 treatment and up-regu-lated upon NAC treatment. Suppression of intracellular GSH by treatment with As2O3 has been shown to increase sensitivity to adriamycin. Conversely, elevation of intra-cellular GSH by treatment with NAC leads to increased drug resistance. The integrated microfluidic chip is able to perform multiparametric pharmacological profiling with easy operation, and thus holds great potential for extra-polation to the cell based high-content drug screening.