Hong Kong's Department of Health on Friday ordered the wholesaler of a proprietary Chinese medicine to recall from consumer a batch of "Hua Tuo Brand" Baoying Dan which has been found to contain excessive mercury.

The action is called for after a surveillance sample from the above batch obtained by Department of Health inspectors from the market is found to contain about two times the permitted limit of mercury.

The drug is known to be used by children for the treatment of generalized discomfort like restlessness at night or fever.

Initial investigation found that the batch of Baoying Dan was manufactured in the Chinese mainland and imported by Hong Kong wholesaler, Wah Ning Chinese Medicine Co.

A spokesman from the Department of Health explained that acute mercury poisoning can cause inflammation of the mouth while prolonged exposure can damage the neurological system and kidneys. Young children are particularly vulnerable.

The matter has been referred to the mainland's drug regulatory authority for their continued investigation.