Short article asking for retraction of the paper by Borba et al. (Jama Network Open, 2020) due to the use of a potentially lethal dose of chloroquine in the clinical trial. As we show, the study attempted to follow the dose recommended by the Chinese consensus of specialists, but accidentally (almost) doubled such dose because of a confusion between dose expressed in salt (chloroquine diphosphate) and dose expressed in base. Moreover, the dose used in three days is more than twice the limit dose described in the Brazilian insert package.