The difficulties are especially obvious for restaurants and families in South China, where people grow up drinking nutritious soups with herbs in them. Duzhong, or eucommia bark, for instance, is cooked in soup with pork kidney to replenish energy in men's kidneys. Ginseng, angelica and lily bulb are boiled together to replenish energy, and benefit the lungs.

Other common ingredients used as foods and herbal medicines include Chinese jujube, lotus seed, medlar fruit, longan and gastrodia tuber. The fresh leaves of mint, basil, milk vetch and baical skullcap are also being used in dishes, according to Jiao.

Jiao recommends eating nutritious foods according to different seasons, individual physical conditions and location.

He says foods that raise energy in spring include sprouts and the liver of chicken, pork and lamb to replenish energy in the liver.

"Summer is a time to replenish energy mildly, and dispel heat and dryness," he says. "It is good to eat lotus seed, mint, water chestnut, pigeon, beef and duck."

For autumn, he suggests frying lily bulb with gingko, and making dishes with orange and pear. In winter, beef and lamb, as well as venison are all good energy boosters, he says.

"My concept of medicinal food is about scientific, nutritional cooking," Jiao says. "It should be an advanced phase of development for Chinese cuisine, instead of a simple mixture of herbal medicine and food."

Jiao thinks people should divide medicinal ingredients into those with light medicinal properties and those with strong medicinal properties, which should only be prescribed by doctors.

"Those herbal medicines that can be mixed with foodstuff to treat illnesses should be left for doctors to decide," he says. "As to those that are also foodstuff, people should be reminded of their side effects, but they should not be banned from using them."