The warning applies to professional horticulturists or those who like gardening.

Zeng Yi, a professor of the Department of Virology of the academy, said that after 10 years of research, he has isolated 52 plants that carry promoters of Epstein Barr (EB) virus.

Unlike most common flowers and plants, the 52 plants, such as Radix Tinosporae (Arrow-shaped Tinospora Root), Codiaeum Variegatum (Variegated Leafcroton), and Lignum Sappan (Sappan Wood), pose danger after long periods of contact with them, usually years of frequent contact. For example, constantly touching the soil where the plants grow or inhaling their pollen, according to Zeng.

Although the medical value of most of the 52 plants has been established through clinical tests, these plants actually have the capacity of becoming carcinogenic, he said.

In other words, some Chinese could be poisoning themselves with their flowers. In Beijing, Shenyang and Guangzhou, many flowers stores are selling Herba Euphorbiae Milii (Crown-of-thorns Euphoriae Herb) and Codiaeum Variegatum. Some residents like planting Codiaeum Variegatum and in some parks in these cities, the Codiaeum Variegatums is often used as a decorative plant.

However, Ma Xiaojun, a professor in the Institute of Medicinal Plants of China, pointed out that most plants on the list can rarely be found or bought in public markets, and also noted that although some of them are used for decoration, they will not harm people's health if they are handled properly.

In fact, he added, if people do not eat the plants nor let them touch open cuts or scrapes the plants in themselves are quite safe.

Ma said that the medical point of view is that any part of any of these plants that can cause cancer must do so by interfering with DNA in some way.

Niu Xiping, a plant expert with the Chinese Academy of Science, said the makeup of plants is complex and even if a plant carries carcinogens, they will not necessarily be active factors in causing cancer.

(China Daily July 9, 2002)