The stock went down by 1.95 per cent to settle at Rs 3,071.45 on BSE. During the day, it slipped 2.24 per cent to Rs 3,062.30.
On NSE, it declined 2.13 per cent to close at Rs 3,070.95.
The drugmaker had earlier said the company was under the scanner of the Department of Justice of USA for alleged violations of some provisions of the Consumer Product Safety Act.
"Dr Reddy's believes that it has complied with all applicable requirements of the Consumer Product Safety Act, including applicable packaging and reporting requirements," the company said in a statement today.
"However, according to a recent letter from the US CPSC, the Commission has decided to refer the matter to the US Department of Justice, with the recommendation that the Department initiate action," it said.