The effects of 4-aminoantipyrine (AAP) on oxidative stress induced by glutathione (GSH) depletion in single human erythrocytes were investigated using microfluidic technique and fluorescence imaging. Most cell-based toxicity evaluations on GSH are performed with bulk experiments based on analysis of cell populations. This work established a single-cell toxicity evaluation method to statistically analyze the GSH amount in single erythrocytes incubated with AAP in different concentrations. The experimental conditions of cell flow rate and cell concentration were optimized. The GSH contents in erythrocytes decreased with increasing dose of AAP. At low concentration, AAP had a little effect on GSH; while at high concentration, MP led to GSH depletion reaching a maximum of 14.53%. The depletion of GSH leads to a significant shift to a more oxidizing intracellular environment. This study provides basic data for presenting the effect of MP on GSH in erythrocytes and is helpful for understanding its toxicity during the blood transportation process. In addition, it will also complement studies on the environmental risk assessment of AAP pollution. (C) 2011 Elsevier B.V. All rights reserved.