Abstrak
Self-medication is the act of self-treatment without a doctor’s prescription which, if done correctly, can help reduce the burden on health services. A good level of knowledge about self-medication of diarrhea is very important to ensure proper use of drugs and prevent unwanted side effects. This study aims to determine the level of knowledge of class XI students of SMK Negeri 1 Purwosari Gunungkidul about self-medication of diarrhea drugs. This research used descriptive observational method with purposive sampling techniques, involving 67 students as respondents. Data were collected through a questionnaire containing 17 statements, including indicators of knowledge about diarrhea self-medication, drug use, dosage, side effects, and contraindications. The total population of 559 students then the calculation using the slovin formula obtained 67 students. Data were collected and the results were then calculated to be categorized as good, sufficient, and less. After scoring, data were analyzed in descriptive form. The result of this study indicate the level of knowledge of class XI students of SMK Negeri 1 Purwosari Gunungkidul who are well informed as many as 14 respondents (20%), who are moderately informed as many as 45 respondents (67%), and who are less knowledgeable as many as 8 respondents (12%). Conclusion.