Abstract: Objective To provide a rational pharmacotherapy of phenformin by investigating the lactic acidosis induced by phenformin. Methods 174 lactic acidosis cases of phenformin were statistically analyzed. Results Male female ratio was 1.4:1, 76.8% of the patients were over 60 years old. For 75.3% of the cases, the dosage of the drug daily was more than 75 mg. For 70.3% of the patients, drug use time was more than halfa year, 92.0% of cases had the induced factors, 63.2% of the patients were cured or improved, 64patients died(36.8%). Conclusion Phenformin can cause lactic acidosis, severe cases can lead to organ failure, and even death. When using this drug should consider carefully the age, usage and dosage, course of treatment and other related factors, ensure rational drug use so as to reduce the incidence of adverse drug reactions.

Key words: phenformin, adverse drug reaction, lactic acidosis, safty of medication, rational administration