Background: Many concoction recipes experience Medication Errors. The most widely used medication is concoction prescription. As many as 95.50% of prescriptions experience potential medication errors. The prescribing stage has a higher percentage which reaches 49%, then followed by the administration stage of 26%, transcribing (11%). Medication errors that reach 62.7% can lead to therapy failure, which consists of failure to detect drug interactions, history of allergies and lack of clinical monitoring, which can lead to failure of drug therapy for patients. Objective: To find out the percentage of medication errors in prescriptions for children's polyclinic concoctions at the Kardinah Regional General Hospital (RSUD), Tegal City. Methods: The study was conducted using a prospective method for data collection and information on child poly concoction prescriptions taken in the period March - May 2023. The research design used cross-sectional, which is a study conducted in a certain place and in a relatively short period of time. done at the same time. Results: in the prescribing phase there was no doctor's SIP 100%, no patient's height 87%, no body weight 84%, and no doctor's initials 100%. in the dispensing phase the most common component was the wrong number of drugs with a total of 2 events with a percentage of 1.50%. In the administration error phase, the results of the study found that errors often occurred, namely patients were not given an explanation of contraindications 72% (107 prescriptions), did not explain side effects 87% (118 recipes), did not explain beyond use date 59%. Conclusion: The highest incidence of Medication Error was in the prescribing phase with a percentage of 67.93%, in the dispensing phase the incidence of Medication Error was 0.30%, and in the administration phase the occurrence of Medication Error was 31.76%.