What is gotu kola (bua bok), and what is in it?

Gotu kola, called bua bok (บัวบก) in Thai, is Centella asiatica, a small creeping plant in the family Apiaceae, the same family as carrot and coriander. In Thailand it is everyday food: the leaves and stems are eaten fresh beside spicy dishes and blended into a green drink. The compounds most often measured in it are four triterpenes, and Thai studies show that how much the plant contains depends on the plant part, the province and the time of harvest.

In short:

• What it is: Centella asiatica (L.) Urban, family Apiaceae; Thai name bua bok
• Other names: gotu kola, Asiatic pennywort, Indian pennywort
• Main compounds: asiaticoside, madecassoside, asiatic acid and madecassic acid; Thai leaf samples also contain terminoloside
• Amounts: 19.5 mg/g in dried leaves (comparing plant parts); samples compared by province and season ranged up to 37.4 mg/g (the abstract does not say which part was measured)
• Watch out for: people who are pregnant, breastfeeding or on regular medication should ask a doctor or pharmacist before using gotu kola products

What plant is bua bok, and what else is it called?

Bua bok is a low, creeping plant. Its scientific name is Centella asiatica (L.) Urban, and an older name for it is Hydrocotyle asiatica. It belongs to the family Apiaceae, the same family as carrot, coriander and dong quai.

Names in different languages

Memorial Sloan Kettering lists the common names Indian pennywort, Hydrocotyle and Mandukaparni. NCBI Taxonomy gives Asiatic pennywort as its English name, together with gotu kola and the Chinese name ji xue cao.

Is gotu kola the same as kola nut?

No. The names sound alike, but Memorial Sloan Kettering points out that gotu kola should not be confused with kola nut. Gotu kola contains no caffeine and has not been shown to have stimulant properties.

Where does bua bok grow, and how is it eaten?

Memorial Sloan Kettering describes gotu kola as an evergreen perennial that is common in East Asia and in many parts of South Africa.

Bua bok in Thai food

In Thailand, bua bok is a vegetable first. The fresh leaves are served as a side vegetable (ผักเคียง) with spicy dishes, and the leaves are blended with water and strained to make nam bai bua bok (น้ำใบบัวบก), a green drink sold at markets. Because it is usually eaten raw, how it is grown and handled also matters (see the section on fresh bua bok below).

Bua bok in neighbouring countries

Bua bok is also eaten widely in Vietnam. A 2024 study by Truong and colleagues collected 26 bua bok accessions from across Vietnam and Laos and grew them side by side under the same conditions in Hue, central Vietnam. The yield per tray ranged from 107 g for the lowest accession to 478 g for the highest, showing how much plants of the same species can differ even when grown in the same place.

What compounds are in bua bok?

The compounds most often used to describe the quality of bua bok are four pentacyclic triterpenes: two glycosides (a triterpene joined to sugars) and the two acids they are built on. A 2012 study by Puttarak and Panichayupakaranant of Prince of Songkla University names asiatic acid, madecassic acid, asiaticoside and madecassoside as the main ones.

The four main triterpenes

Source: formulas and molecular weights from PubChem. Madecassoside differs from asiaticoside by one extra oxygen atom, and the same is true of madecassic acid and asiatic acid. The glycosides are roughly twice as heavy as the acids because of the sugar chain attached to them.

What else has been found in Thai bua bok?

A 2026 study by Maliwong and colleagues at Khon Kaen University and the Chulabhorn Research Institute looked closely at bua bok leaves collected in Thailand. The researchers isolated and identified 18 compounds, including two polyacetylene glucosides that had not been described before, which they named centellatriolosides A and B.

They also found a third triterpene glycoside, terminoloside, in large amounts. It had not been reported in Thai bua bok before, and it appeared consistently in three more samples from other sources. According to PubChem, terminoloside has the same molecular formula as madecassoside (C48H78O20), so the two are isomers: the same atoms arranged differently. The study tested a conventional HPLC method on six related triterpenes, the three glycosides and their three acids, and found that pairs of isomers were still hard to separate completely. The researchers concluded that more advanced methods are needed to assess the quality of bua bok.

Which part of bua bok has the most triterpenes?

The leaves. Puttarak and Panichayupakaranant (2012) separated bua bok into six parts, dried each one, and measured the four triterpenes.

The abstract gives a figure only for the leaves. For the other parts it states only that the leaves were the highest, so no figures are shown for them here.

Do the amounts differ by province and season?

A great deal. In the same study, the researchers compared bua bok grown in different Thai provinces and harvested at different times of the year.

The provinces with the most were not the same in every season: Trang was highest in March and Songkhla in December. The abstract does not say which part of the plant was measured in this comparison, so these figures should not be compared directly with the 19.5 mg/g for leaves. The limits of these data: the abstract reports only the highest and lowest groups, and the samples came from a limited number of provinces, so the figures show how much bua bok can vary rather than how much is in the bua bok sold at any one market.

Does the age of the plant matter?

Yes. A field trial by Thong-On and colleagues at Mahidol University (2014) grew one tetraploid line (a plant with four sets of chromosomes, produced in the laboratory) and three ordinary diploid lines of bua bok. In all four lines, growth, yield and triterpene content reached their highest point 4 months after planting. The tetraploid line had larger leaves, longer leaf stalks and a higher dry weight per area (77.53 g per square metre). This was a single field trial, so it shows the effect of harvest time under one set of conditions.

Is fresh bua bok from the market clean?

Because bua bok is usually eaten raw, washing it well before eating matters. A survey by Laoraksawong and colleagues (2025) bought 1,800 fresh vegetable samples from 12 markets in Bangkok and nearby areas between November and December 2022 and checked them under the microscope.

The survey also found that vegetables from open-air markets in rural areas were 1.40 times more likely to be contaminated than those from structured markets in urban areas. The researchers called for better hygiene during growing, harvesting, transport and storage. The limits: the survey covered one area and two months, and it checked for contamination by microscope rather than looking at any effect on people.

Is there a recommended daily amount of bua bok?

No. Bua bok is a plant, not a nutrient, so it has no value in the Thai Reference Daily Intakes (Thai RDIs), which cover nutrients such as vitamins and minerals. As shown above, the amount of triterpenes in bua bok also differs widely from plant to plant, season to season and province to province.

Who should be careful with gotu kola?

Effects that have been reported

Memorial Sloan Kettering lists skin rash and harm to the liver (liver toxicity) as side effects that have been reported in people using gotu kola. Anyone with an ongoing health condition or taking regular medication should speak to a doctor or pharmacist. Memorial Sloan Kettering also notes that, depending on where gotu kola is grown, the amount of the compounds measured in it can vary widely.

People taking regular medication

Memorial Sloan Kettering says lab studies suggest gotu kola may affect the enzymes the body uses to break down some medicines, although how much this matters in practice is not yet known. Anyone taking regular medication should speak to a doctor or pharmacist before using gotu kola products, and tell their healthcare providers about any herbs or supplements they take.

If you are pregnant, breastfeeding, take regular medication or are under a doctor's care, speak to a doctor or pharmacist before taking dietary supplements.

Dietary supplements are not intended to prevent, treat or cure any disease.