In many developing countries, the value of knowledge is in its capacity to save and enhance human lives. The absence, loss or restriction of such knowledge impacts at the lowest levels of disadvantage and poverty, in death and disease. Essential components of an effective health service are medicines and skilled human resources. This paper highlights the restricted availability of these resources--a situation that arises because of deliberate policies that adversely affect knowledge flows towards the poor. We focus in particular on intellectual property rights and the mobility of highly educated health professionals (the "brain drain") and how the ensuing knowledge flows affect health systems and their ability to respond to the often worsening health situation in many countries, particularly in the context of HIV/AIDS. We conclude that urgent steps need to be taken to address the facilitators of human resource outflows and the inhibitors of intellectual capital inflows in sub-Saharan Africa.