OBJECTIVES: The aim of this work is measure the efficiency of this rule that established PMVG for public medicine purchase. METHODS: Two lists were built, one with PMVG (PMVG databank), established by CMED, and the other list contains the public prices acquisitions before and after the enacted CAP legislation (Health Price Bank – BPS databank). The lists were separated in two groups. The first contains the prices of PMVG databank and BPS databank between 2004 and 2006 (group 1), and the second complains the prices for the period between 2007 and 2012 (group 2). The comparison of two groups, before CAP (group 1) and after CAP (group 2), was conducted by Student t-test one-tailed of the mean medicine prices (significance level of 5%, assuming unequal variances). RESULTS: CMED implemented The Price Adequacy Coefficient (CAP) by publishing the Resolution CMED nº 04 on 18^thof December of 2006. It is a mandatory minimum discount to be applied by pharmaceutical companies and distributors in the Factory Price of medicines (PF) authorized, resulting on a public price cap (PMVG). There is no evidence of the efficiency, or the real need for this regulatory activity performed by CMED geared to the drug public acquisitions.The list resulted in a selection of 68 medicines. Fourteen (14) medicines had an average BPS price before CAP less than or equal to the average BPS price after CAP, however, only 4 were statistically significant (α ≤ 0.05). In contrast, 47 medicines had an average BPS price after CAP significantly lower or equal to the average BPS price before CAP (α ≤ 0.05). CONCLUSIONS: It is concluded that this CMED legislation is economic and social efficient.