Diarrhea is bowel movements with a soft or liquid consistency, it can even be just water with a frequency that is more frequent than usual (three times or more) in one day. Self-medication is a treatment carried out by the community without a prescription from a doctor. The purpose of this study was to describe the level of knowledge of parents about self-medication of diarrhea in children in Vim Kotaraja Village. This research was conducted in May 2021 in the village of Vim Kotaraja. The number of samples in this study were 97 respondents. This research uses purposive sampling method. The results showed that the age of the respondents who were more dominant, namely 26-35 years, was 53 respondents (55%), the dominant gender was 92 respondents (95%), the last education was more dominant, namely SMA/SMK education of 62 respondents. (62%). The level of knowledge of parents about diarrhea in children is mostly good, as many as 95 respondents (98%). The level of knowledge of parents about self-medication was mostly good, as many as 71 respondents (73%). The actions taken by parents when their child had diarrhea mostly did self-medication by 73 respondents (75%) while those who chose to go to the doctor were 24 respondents (25%). The type of drug used by parents when their child has diarrhea is choosing the Entrostop drug as many as 43 respondents (44%). From the results above, it can be concluded that the level of knowledge of self-medication, actions, and the types of medicine used when the child has diarrhea is good.