Yet medicinal herbs that send patients pinching their noses and gagging were once natural beauties. They were fresh dewy plants that only took on a sinister air after processing.
Herb-lover Chan Sik-yan took Young Post on a tour of the Hong Kong Olympic Trail in Mui Wo to point out some of nature's medicine.
The ancient healing art of Chinese medicine dates back more than 5,000 years. Practitioners have recorded some 6,000 species of plants with medicinal value. A quarter of them can be found in Hong Kong.
If you know where to look, they are everywhere: abandoned rice paddies, roads, and the park just around the corner.
"For a city this compact, we have an impressive plant diversity," Chan says. "It is easy to spot dozens of medicinal plants in a matter of hours."
Cotton tree and white jade orchid are fairly easy to find, but the critically endangered Hong Kong witch-hazel and Hong Kong Asarum are hard to spot.
With a guide, beginners can start identifying plants by their flowers and fruits, and then move on to leaves. Bark and roots require keener eyes and more experience to recognise.
Here are some of the remarkable herbs we spotted on our excursion:
Sensitive plant (Mimosa pudica)
When this short shrub is gently tapped, the tiny fern-like leaves fold inward and wilt as if dead. This is caused by a drop in the internal pressure of the leaves' cells.
The tea made by simmering the whole plant, including its flowers, has a calming effect and can be used to treat coughs. It has a mild anaesthetic effect as well.
Water banyan (Cleistocalyx operculatus)
Every herbal shop boasts its unique "24 flavours" tea formula, but all of them will have a key ingredient - water banyan.
Along riverbanks in spring, the trees' branches are heavy with white puff-like flowers. But it is in the greenish buds that the essence of its remedial power lies. Once sun-dried, dampened and fermented in a dark room, the buds can be made into a powerful bitter/sour concoction to treat heatstroke.
Rough-leaved holly (Ilex asprella)
Its knobbly green stems and broad leathery leaves set this plant apart from the forest crowd. The Chinese University of Hong Kong first introduced it to the territory for its medicinal leaves. Researchers invented a formula to treat the flu by chopping, grinding and mixing the roots and leaves of the rough-leaved holly and its two relatives - tarajo and kurogane holly - together.
Night-scented Lily (Alocasia odora) \
Casual hikers may mistake the lily's huge heart-shaped leaves and starchy underground plant stem for taro, but take heed. The stem contains toxic acids that can numb and swell the tongue, causing difficulty in breathing, and throat pain.
In the old days, residents of remote villages used this plant as a last resort to tackle severe flu and malaria. They soaked the stems for days, and stir-fried them with rice until they turned black, to dilute the toxin, and then boiled the plant. But if anything goes wrong in the complicated procedure, toxins may remain and the medicine will turn into poison.
So, don't try brewing up your own potions at home. "The inexperienced might mix poisonous plants with the right ones," Chan warns. "The results could be fatal."
The Hong Kong Health Association's next traditional Chinese medicine walking tour sets off on July 31. Visit www.hkha.org.hk for details