OBJECTIVE： To investigate related factors for valproic acid-induced fibrinogenopenia in epilepsy patients. METHODS： A retrospective survey was conducted to collect the epilepsy patients treated with routine dose of valproic acid regularly more than one week in Epilepsy Diagnosis and Treatment Center of Xuanwu Hospital， Capital Medical University during Jan. 1st， 2017 to Mar. 1st， 2017. The general situation， drug use （dosage of valproic acid， dosage form of valproic acid， drug combination）， liver function， blood routine indexes and coagulation indexes， etc. were collected. Univariate and binary Logistic regression analysis were used to analyze the relationship of above factors with fibrinogenopenia. ROC curve was used to screen and predict the cut-off points when sensitivity and specificity of fibrinogenopenia were good. RESULTS： A total of 59 valid cases were collected， including 40 male （67.8％） and 19 female （32.2％）； 35 patients （59.3％） were under 14 years of age， and 24 patients （40.7％） over 14 years of age， with average age of （17.2±15.7）. Of these， 24 had fibrinogenopenia （40.7％）. Univariate analysis showed that fibrinogenopenia was negatively correlated with age （P＝0.042）， but was positively correlated with dosage of valproic acid （P＝0.003）； fibrinogenopenia was not correlated with gender （P＝0.679）， dosage form of valproic acid （P＝0.790） or drug combination （P＝0.502）. Binary Logistic regression analysis showed that dosage of valproic acid and neutrophil percentage， erythrocyte count and platelet count of patients were related risk factors of fibrinogenopenia； odds ratios of related risk factors were 1.101， 0.925， 0.132， 0.976. ROC curve showed that the area under the ROC curve which was correlated with dosage of valproic acid was 0.766， sensitivity and specificity were 98.5％ and 54.3％； the cut-off dosage was 13.311 7 mg/kg. CONCLUSIONS： The greater the dosage of valproic acid and the younger the age， the greater the possibility of the fibrinogenopenia. For patients with long-term use of valproic acid， even if the normal dosage are used， it is necessary to monitor fibrinogen changes regularly， for whom the dosage are greater than 13.311 7 mg/kg， the frequency of fibrinogen monitoring should be increased.