Have India’s Poor Become Human Guinea Pigs?

Drug companies are facing mounting pressure to investigate reports that new medicines are being tested on some of the poorest people in India without their knowledge.

"We were surprised," Nitu Sodey recalls about taking her mother-in-law Chandrakala Bai to Maharaja Yeshwantrao Hospital in Indore in May 2009.

"We are low-caste people and normally when we go to the hospital we are given a five-rupee voucher, but the doctor said he would give us a foreign drug costing 125,000 rupees (£1,400)."

The pair had gone to the hospital, located in the biggest city in Madhya Pradesh, an impoverished province in central India, because Mrs Bai was experiencing chest pains.

Their status as Dalits - the bottom of the Hindu caste system, once known as untouchables - meant that they were both accustomed to going to the back of the queue when they arrived and waiting many hours before seeing a doctor.

But this time it was different and they were seen immediately.

"The doctor took the five-rupee voucher given to BLPs [Below the Poverty Line] like us and said the rest...