Chinese authorities revealed that they are investigating allegations that pharmaceutical companies are using gutter oil in the production of antibiotics rather than using the more expensive soybean oil.
According to the BBC, gutter oil is reprocessed kitchen waste dredged from restaurant drains.
The government said it would release its findings soon, and did not give further details.
According to the report, in April, state-run media reported on how officials cracked down on underground workshops that used decomposing animal fat and organs to produce gutter oil.
Police said that most of the oil was sold to oil manufacturers for food production and making hotpot soup in restaurants.
In September last year, police also arrested 32 people in an operation to prevent the sale of gutter oil as cooking oil, the report added.