In tropical regions millions of people still live at risk of malaria infection. 
Indeed the emergence of resistance to chloroquine and other drugs in use in 
these areas reinforces the need to implement alternative prophylactic 
strategies. Genistein is a naturally occurring compound that is widely used as a 
food supplement and is thought to be effective in countering several 
pathologies. Results presented here show that genistein inhibits liver infection 
by the Plasmodium parasite, the causative agent of malaria. In vitro, genistein 
decreased the infection rates of both mouse and human hepatoma cells by 
inhibiting the early stages of the parasite's intracellular development. Oral or 
intraperitoneal administration of genistein decreased the liver parasite load of 
P. berghei-infected mice. Moreover, mice fed on a genistein-supplemented diet 
showed a significant reduction in Plasmodium liver infection as well as a 
reduced blood parasitemia and partial protection from severe disease. Since 
genistein is a safe, low-cost, natural compound that can be used permanently in 
a diet, we propose its use as a prophylactic agent against malaria for endemic 
populations and long-time travelers.