OBJECTIVE To investigate the Maillard reaction conditions between famciclovir and lactose in oral solid dosage and to establish methods of monitoring Maillard reaction productions(MRPs), to guide formulation development. METHODS According to the Maillard reaction mechanism and the manufacture process of the solid dosage form, selected water, temperature and time as the main research conditions, used visual inspection and differential scanning calorimetry to conduct preliminary evaluation of the Maillard reaction, used HPLC and LC-MS to identify and control MRPs. RESULTS When the water ≤ 10% and the temperature ≤ 90℃, famciclovir was good at compatibility with lactose and did not cause the Maillard reaction, the method of HPLC could be used for quality control of MRPs. CONCLUSION When famciclovir combined with lactose in the development of oral solid dosage forms, water and temperature should be controlled for reducing the risk of producing Maillard reaction.