BEIJING, June 15 -- China's top market regulator unveiled a trial guideline on Thursday to improve the regulation of the blind-box industry.

The document, released by the State Administration for Market Regulation, banned some items from being sold in these boxes, including medicine, medical equipment, live animals, and flammable and explosive objects.

Sales of these boxes to minors under the age of eight are prohibited, said the document, urging vendors to keep minors from becoming addicted to playing with blind boxes.

Merchandisers should publicize information about the value of the blind boxes' contents, the rules for drawing these boxes, and the probabilities of the outcomes, per the document. They are also encouraged to help maintain shoppers' rationality by setting caps on monetary spending and the number of purchases.

The guideline also banned blind box contents that offend social morality and public order.