Kerala doctors have called for a state ban on an experimental drug that can cause blindness in patients.
Dr K. K. Krishna, a professor of ophthalmology at the Ernakulam Medical College, said he had seen patients die from the drug.
The drug, called nevirapine, is one of the few approved by the World Health Organisation (WHO).
Krishna told reporters that his patients died of the drug and he would like to know why.
The government has denied that it has approved nevirapsine and said the drug could only be used in special circumstances.
The Indian drug regulator said nevirapeptine was approved for treatment of severe eye problems and had been shown to be safe in clinical trials.
The use of nevirampine is illegal in India and can lead to death if used for more than three months.