It is important when developing effective and safe pharmaceutical products to select adequate active components and formulations as well as to design their containers and devices. Minoxidil was developed as a direct over-the-counter (OTC) drug in 1999 and has long been marketed only by one original company. Recently, many generic products have been marketed. However, the shape and type of the containers for these generic products differ from that of the original product, leading to a possibility that the amount of minoxidil applied by patients may differ. In the present study, the original and three typical generic products with 5% minoxidil external formulations were evaluated for their filling amounts, single application amounts, extent of distribution on application, ability to reach the scalp, and dripping properties. As a result, statistically significant differences were found in the filling amounts and ability to reach to the scalp between the products due to differences in the nozzle shape of the container. In addition, a large variation was observed in some of the generic products in terms of the drug liberation. These results indicate that it is important to suitably design and adequately evaluate the container for OTC products such as minoxidil formulations, which can exhibit toxicity from overuse, and that are easily purchased by consumers.