Objectives: to evaluate the safety and effectiveness of the clonidine preparation at a concentration of 15 μg / mL used for oral premedication in children between one and seven years old at a dose of 4 μg / kg of weight undergoing ambulatory surgery between February and October 2019 at the San Marcel Clinic. Materials and methods: a restrospective, descriptive observational cross-sectional study was carried out, with consecutive sampling during the study period. The data of 202 patients were obtained from the medical history to then perform the univariate and bivariate analysis with descriptive statistics. P value > 0,05 was considered significant. Results: there was an incidence of preoperative anxiety of 2,5%, arterial hypotension of 30,69% and bradycardia of 23,26%. There were no cases of postoperative vomiting, chills, or respiratory depression. Age was associated with preoperative anxiety (P = 0,03) and bradycardia (P = 0,049) but not with arterial hypotension (P = 0,066). Conclusions: master clonidine preparation is associated with low incidence of preoperative anxiety in children and absence postoperative respiratory vomiting, chills, and depression. However, there is concern about the high frequency of low blood pressure and bradycardia found without any association being raised.