When considering the use of pharmaceutical drugs during pregnancy and lactation, two concerns must be weighed against each other: the potential deleterious effects on the fetus and the possibility that treatment necessary for the woman but risky for the fetus either cannot be administered or else the woman must give up the pregnancy or give up nursing. The main roadblock to weighing these two concerns is a lack of evidence about what drugs are harmful to the fetus. Establishing this evidence is important to implementing the “Choosing Wisely” policy. In 2005, Japan established the Japan Drug Information Institute in Pregnancy (JDIIP), which addresses issues regarding treatments with pharmaceutical drugs during pregnancy and lactation. The JDIIP has analyzed data regarding the pregnancy results of patients who have received counseling and has conducted a registration survey, analyzed post-marketing survey data from pharmaceutical companies, and measured drug concentrations in breast milk. Currently, the JDIIP is increasing the number of targeted drugs about which it is collecting evidence. In addition, it is re-evaluating the published literature and implementing a project to revise drug packaging inserts. Pharmacists are expected to implement the “Choosing Wisely” policy regarding pharmaceutical treatment during pregnancy and lactation and to contribute to the collection of new evidence.