OBJECTIVES: To asset the cost-effectiveness relation between racecadotril (Hidrasec®) adjuvant with electrolytes for the treatment of pediatric patients with acute diarrhea from the Mexico’s National Health System perspective. METHODS: A cost-effectiveness analysis was conducted through a decision tree. The model structure was taken from the published economic study (Rautenberg et al., 2012). The analysis compared racecadotril (Hidrasec®) plus electrolytes vs electrolytes by themselves. The effectiveness measure was the absent of diarrhea 48 hours after the administration of the treatment and the proportion of patients that did not require hospitalization. Based on the natural history of the disease, the time horizon was of 6 days. The transition probabilities was taken from the clinic literature (Lehert et al., 2011) (Álvarez et al., 2009). It was only considered direct medical costs, which are pharmacological costs and cost of a hospitalization per day, there were obtained from institutional sources. RESULTS: In a 1,000 patients cohort, racecadotril (Hidrasec®) adjuvant with electrolytes, resulted in the absent of diarrhea 48 hours after the administration of the treatment in 580 patients, in comparison with only 320 patients a cause of only electrolytes, which means an incremental effectiveness of 320 patients. 97.44% and 73.43% of the patients treated with racecadotril (Hidrasec®) adjuvant with electrolytes and with electrolytes alone, respectively, did not require hospitalization, having an increase of 24% because of the use of racecadotril (Hidrasec®). The average cost per patient treated with racecadotril (Hidrasec®) adjuvant with electrolytes was $99.41 USD, in comparison with electrolytes alone that was $354.39 USD, having a saving of $254.98 USD. CONCLUSIONS: From the Mexico’s National Health System perspective, racecadotril (Hidrasec®) adjuvant with electrolytes for the treatment of pediatric patients with acute diarrhea, is a dominant therapy vs electrolytes alone, generating a bigger effectiveness with a less cost per patient.