The sales of isatis root have skyrocketed in the Pingtan Comprehensive Pilot Zone, Fujian province, entering April, amid concerns that H7N9, a new avian influenza virus, may hit the county.

"Isatis root sold out a few days ago. We are out of stock now," said Ms Lin, a drugstore saleslady, to the Pingtan Times.

"People started buying it, and I just followed the trend," said Ms Zhong, a Pingtan citizen.

"It is not expensive. I can afford it," she added, saying the purchase is motivated by safety concerns.

Sales of the medicinal tea have increased at drugstores across the county. But experts warn that it is not a miracle cure and cannot be consumed indiscriminately.

Isatis root does not agree with everyone who catches a cold. From the angle of traditional Chinese medicine, those with the common cold should not take the medicinal tea, said Lin Youning, vice-president of a local hospital.

The sale of poultry imported from outside Pingtan has plummeted in contrast. Many have expressed concerns that live birds may bear the avian influenza virus.

Pingtan reinforced prevention efforts for H7N9 on Sunday.

Edited by Chen Zhilin and Michael Thai