19 October 2019
Tests on Chinese herbal medicine samples revealed high levels of sulfur dioxide in several items, the Democratic Party says. Photo: HKEJ
Tests on Chinese herbal medicine samples revealed high levels of sulfur dioxide in several items, the Democratic Party says. Photo: HKEJ

Warning sounded over sulfur dioxide in Chinese herbal medicines

Hong Kong people are being urged to be more careful when buying Chinese herbal medicines after tests showed some products sold in local shops contained excessive levels of sulfur dioxide.

Citing the results of a study, the Democratic Party said some herbal medicine samples were found laced with sulfur dioxide which can cause serious damage to the human body if taken too much.

Warning the public to pay more attention to the products they buy, the party called on authorities to lay out the safety limit for sulfur dioxide in Chinese herbal medicines, just like they do for food, the Hong Kong Economic Journal reports.

As part of its food surveillance program, the Democratic Party collected 20 samples between August and October from Chinese medicine shops.

The samples, collected in shops in Central, Sheung Wan, Diamond Hill, Sha Tin and Ma On Shan and involving 12 different herbal medicines, were sent to a government-accredited laboratory for tests.

The results showed the amount of sulfur dioxide in eight of the samples exceeded the limit set by the Chinese Pharmacopoeia Commission, an official compendium of drugs that includes information on the standards of purity, description, test, dosage, precaution, storage, and the strength for each drug.

Among the eight, one sample of Radix Angelicae Sinensis, or danggui, contained 1,620mg of sulfur dioxide per kilogram, or 10.8 times higher than mainland China’s limit of not more than 150 mg/kg.

Sulfur dioxide can be found in many Chinese medicines because sellers tend to smoke the herbs for anti-mold purpose so that they can be preserved for a longer term.

The World Health Organization has suggested the acceptable daily intake of sulfur dioxide should not be more than 0.7 mg/kg. That is, an adult weighing 60kg shouldn’t take in more than 42 mg of sulfur dioxide a day.

Professor Karl Tsim, who heads the Center for Chinese Medicine research at the Hong Kong University of Science and Technology, pointed out that sulfur dioxide can turn into hydrogen sulfide that is toxic, after being ingested into the system.

Excessive intake of sulfur dioxide can cause headache, dizziness, lack of strength, vomiting and, in some cases, even result in coma, Tsim said, adding that sulfur dioxide can also increase the chance of contracting lung cancer.

Dr. Helena Wong Pik-wan, a Democratic Party lawmaker, criticized the government for failing to set up a standard to regulate the amount of sulfur dioxide contained in Chinese medicines, describing the lapse as unimaginable and illogical.

She urged the Food and Health Bureau to redress the situation by taking mainland China and international practices as reference, and amend the Chinese Medicine Ordinance as soon as possible.

In response, the Department of Health said an expert panel formed under its Hong Kong Chinese Materia Medica Standards program had suggested that all Chinese medicines go through sulfur dioxide tests, and that an industry-wide consultation regarding the suggestion could begin in the 2018-19 fiscal year.

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