Early micro-cancer detection in the small intestine can be realized using infrared fluorescence endoscopy (IRFE) in conjunction with an infrared fluorescence biomarker. In this paper, we present a third-generation capsule that detects weak fluorescence signals emitted by low concentrations of indocyanine green (ICG). An applicationspecific integrated circuit (ASIC) has been designed and fabricated that integrates many of the peripheral components of the capsule system. The ASIC enables the system to have greater sensitivity whilst reducing the capsule size and lowering the power consumption.