Candy shaped like life-size lightbulbs have proved a big seller in China during the holiday season after going viral online, but a Beijing health expert has warned the treat could be a choking hazard.

Made from caramel, the solid candies－about 10 centimeters long and 6 cm at the widest point－have been popular with shoppers looking for unique gifts on Taobao, the online marketplace.

The novelty became popular thanks to Emergency Medicine Specialist, a soap opera that began to air in China about a month ago.

In the show, a man puts a lightbulb into his mouth out of curiosity and has to be rushed to the emergency room when it becomes stuck.

The lead actress, who plays the hospital's director of ER, helps the patient remove the bulb by breaking the glass and putting wax around the mouth to reduce friction.

One merchant on Taobao who was selling the lightbulb candy for 39 yuan ($6) advertised their product as homemade and said it weighed 200 grams. They had notched 1,026 sales in one month.

However, netizens have raised concerns about safety. Xu Fanchi, an online celebrity, posted a video in which she was unable to remove the candy bulb from her mouth for five minutes. She finally worked it free after the caramel began to melt.

Bi Qingyun, an attending doctor with the ear, nose and throat department at the China-Japan Friendship Hospital in Beijing, warned that the treat could cause more health risks than a real light bulb.

"If the hard sugar candy stays in the mouth for more than one to two hours, the lower jaw joint could be dislocated," she said.

"Once the tongue swells due to the long-term pressure, it can cause choking, which can be fatal."

She suggested consumers avoid putting the entire candy in their mouth. "Don't even risk it out of curiosity," Bi added.