An aircraft flying from Wuhan to Beijing turned back on Wednesday after a passenger began complaining of discomfort.
At 10:23 pm on Wednesday, a micro-blogger on Sina Weibo said flight CA1874 returned in less than an hour after taking off because a passenger felt sick.
The netizen complained the flight had already been delayed for four hours after passengers had boarded.
According to a report from Wuhan-based Changjiang Daily, the stricken passenger admitted that he had a history of drug abuse.
The report also quoted an unidentified staff member from Air China's Hubei office, saying that the flight did not take off until 11 pm on Wednesday, after the passenger was removed from the plane. The delay resulted in the cancellation of a flight from Beijing to Wuhan and a loss of 50,000 yuan ($7,850) to Air China from passenger compensations and fuel costs.