How do we understand how an infection affects the human body? And how do we go about the process of finding safe and effective drugs and vaccines for the many diseases that abound? One way scientists do this is through Controlled Human Infection Studies or CHIS, also known as human challenge studies. This involves deliberately exposing a volunteer to a disease-causing germ, in a controlled environment. This is done to understand the various facets of the infection and disease, and also to speed up the process of finding a cure. India has so far stayed away from such studies, because of the many ethical issues involved: the deliberate harm caused and the potential risk of exploitation since volunteers are paid for their participation, though they have been carried out in other countries. Last month however, the country’s premier medical research body, the Indian Council of Medical Research, released a consensus policy document, arguing the case to bring in human infection studies into our country. What exactly will these studies involve? Do they have any benefits over regular clinical trials? After the world saw the sudden explosion of Covid-19, is there a need for deeper, faster studies of infectious diseases especially with resistance to many drugs increasing? Does India have a robust-enough regulatory system to oversee such trials and to ensure transparency and accountability?