Yet not everyone is happy about the trend. Shanghai student Zhou Mingyang said that in preparation for the exam his parents had given him a host of healthcare products. "I poured most of it away," he said. "It tasted so bad."

While some parents concentrate on food for the brain, others look to food for the soul.

"We get a lot of students and their families at this time of year," said Hou Dongling from Shanghai Confucian Temple. "They come to pray for a good result, as the temple is known for the God of Wisdom. The peak time is usually the weekend before the exam."

Li Yushan, who studies at Shanghai Nanyang Model High School, has already been accepted by Fudan University's medical school, but said she visited the temple for reassurance.

"I also went to Mount Wutai because it's the home of the Bodhisattva of Wisdom, Manjusri," she said. "Many students pray to Manjusri before the gaokao."

Of course, faith and superstition are also big business, one that traders on Taobao - China's largest online marketplace - are capitalizing on.

A search on Taobao for "gaokao" on Tuesday produced more than 870,000 results, with items for sale ranging from study guides to "lucky" stationary sets and T-shirts printed with inspirational messages, such as "Fight for the Exam" and "Put Positive Energy Toward Your Dreams".

One Taobao trader, who did not give his name, said this year he has sold more than 500 colorful T-shirts bearing words of encouragement.