Cystic fibrosis (CF) is a debilitating and often deadly disease. Until recently, the only treatments for its symptoms were difficult to administer and time-consuming. Life-changing new treatments that dramatically improve the prognosis for people with the disease have been developed, but they are expensive and Vertex, the US company making the drugs, has decided against registering the drugs in South Africa. Cheri Nel, a woman living with CF, is now taking Vertex on in a South African court. Catherine Tomlinson unpacks the details.