anti-infective drugs for systemic use (OR=1.99, CI 95%: 1.574-2.525, p<0.001), confusion generated with the name of the drug (OR=1.28, CI 95%: 1.051-1.560, p=0.014), and trouble interpreting prescriptions (OR=1.32, CI 95%: 1.037-1.702, p=0.025) increased the risk for error reaching the patient. Conclusions: It is necessary to develop surveillance systems for medication errors in ambulatory care, focusing on the prescription, transcription and dispensation processes. Special strategies are needed for the prevention of medication errors related to anti-infective drugs.