Health centres of Idjwi district (Zaire) have been self-financed through the selling of drugs since 1985. Medical care is expensive and its use is low (24 visits per year per 100 inhabitants). In 1989 the medical team tried to reduce the cost of visits by changing the prices of drugs and prescriptions. A limited control was set up to assess this intervention. The study showed that although prescribed drug costs were stabilized compared to inflation, there was no increase in the use of medical care. Moreover, the reduction of drug profit margins for health centres seriously affected the health care institution by causing a drop in income. Six months after the intervention the monthly accounts showed a deficit in 6 centres out of 8. The need for health care centres to be self-financing is a major limiting factor in the use of health care in Idjwi district. There are no easy solutions for health centre managers that satisfy both low-cost access to care and health care self-financing. Some minimal financial participation from the state is required. Only then can the concept of financing health care through the selling of drugs be operational.