CQ resistance is both spreading and continuing to evolve via additional selective pressure. Continued evolution of CQ resistance, artemisin resistance, MQ resistance, QN resistance and so on, continuously produces new genotypes and pharmacologic phenotypes. When resistance to multiple drugs is seen, the strain is often called multidrug resistant (MDR). Molecularly speaking there are many MDR genotypes. Thus, a sometimes overlooked aspect of antimalarial drug discovery is that we are only in the midst of an ongoing phenomenon; what is relevant for one subspecies of CQR P. falciparum is not necessarily relevant for another. It is crucial to understand 'subtypes' of CQ resistance and to develop inexpensive therapy that is effective against multiple subtypes.