Eri Machii, a 37-year-old pharmacist, hopes a traditional Japanese method of marketing medicine will take off in Africa and help improve health care.

The method is called okigusuri, in which a sales representative brings a variety of medicines to a client's home without requiring any deposit or advance payment. The medicines are stored in a free box given to the client.

Clients have no obligation to buy any of them but pay only for what they have used when the sales representative comes around the next time. The representative then restocks the box.