OBJECTIVE To provide reference for standardizing the labeling of medication information for pregnant women and lactating women in the instructions of antiarrhythmic drugs. METHODS The instructions of antiarrhythmic drugs were collected from the terms of “medication reference ”on official website of Yimaitong Technology Co. ，Ltd. The labeling of medication information of pregnant women and lactating women were sorted out ，counted and analyzed with reference to the Detailed Rules for Specifications of Instructions of Chemical Drugs and Therapeutic Biological Products issued by the State Food and Drug Administration. RESULTS A total of 111 instructions of antiarrhythmic drugs were collected in this study ，of which 102 instructions were marked with “medication for pregnant women ”（91.89％），of which the proportion of those with medication guidance and without medication guidance were 75.68％ and 16.22％ respectively. Eighty-eight drug instructions were marked with the item “medication for lactating women ”（79.28％），of which the proportion of those with medication guidance and without medication guidance were 70.27％ and 9.01％ respectively. Among different categories of antiarrhythmic drugs ，the best labeling of “medication for pregnant women ”was class Ⅰ antiarrhythmic drugs （100％），while class Ⅲ drugs（25.00％）were most missing ； class Ⅳ antiarrhythmic drugs （94.44％）were the best labeled for “medication for lactating women ”，while class Ⅰ（26.47％）were the most missing . There were differences in the labeling contents of “medication for pregnant women ”and“medication for lactating women ”in some drug instructions of the same variety from different manufacturers. Among the 99 drug instructions of domestic pharmaceutical enterprises ， 92 listed the items of “medication for pregnant women”and“medication for lactating women ”，and the proportions of them with medication guidance were 74.75％ and 69.70％ respectively；among the 12 drug instructions of foreign pharmaceutical enterprises ，10（83.33％）listed the items of “medication for pregnant women ”and“medication for lactating women ”，and the proportion with medication guidance was 83.33％ and 75.00％ respectively. CONCLUSIONS There are some problems in the labeling content of domestic antiarrhythmic drug instructions，such as the lack of information related to “medication for pregnant women ”and“medication for lactating women ”， the confusion of guidance expression ， the inconsistent content of drug instructions of the same variety from different manufacturers，the lag of modification and update ，and the poor standardization of drug instructions. Drug supervision and administration departments and drug manufacturers should pay attention to them and constantly strengthen the management and standardization of instructions.