The Centre for Health Protection is investigating a suspected food poisoning outbreak affecting two men and four women.
They felt ill after eating fresh Jin Zhen purchased from a fresh market in Tung Chung on July 17.
Four required hospitalisation and they have already been discharged.
The centre advised people to soak fresh Jin Zhen well in water and cook it thoroughly, to avoid being affected by a natural toxin in its root and floral part.
