Khadira: Benefits, Evidence & Safety

TL;DR

Khadira (Acacia catechu) is a tannin-rich heartwood used in Ayurveda for skin and digestive complaints; its katha is catechins. Human trials tested only combinations with Chinese skullcap for knee osteoarthritis, one matched naproxen, but postmarketing reports linked that blend to rare liver and lung reactions. Animal studies show blood-sugar and anti-inflammatory effects; standalone khadira has no human data.

What it is

Khadira is Acacia catechu Willd., a deciduous tree indigenous to India, other Asian countries, and East Africa, known as kattha, khadir, or khair (Stohs & Bagchi, Phytother Res 2015). The medicinal material is the heartwood, boiled in water and evaporated to a concentrated extract called katha (catechu): a process that yields a product historically prized for its high tannin content (same review). One analyzed heartwood extract contained 66.9% catechin and 23.1% epicatechin, 90% of its composition, with the astringent, tanning, and antioxidant properties attributed to these gallic-acid-derived polyphenols (same review).

Traditional use

In Ayurveda, khadira is classified as a Kashaya Rasa Pradhana Dravya (a predominantly astringent-tasting substance); Charaka described it as the drug of choice in Kushtha (skin disorders) (JAIMS comprehensive review, 2025). Khadirarishta, a fermented tonic prepared from the bark and heartwood, is a well-known Ayurvedic skin preparation, and the heartwood extract appears in formulations such as Lavangadi Vati (Ismail & Asad, J Young Pharm 2009, via PMC). Traditional applications catalogued in a 2015 review include use as an antimicrobial, anti-inflammatory, antifungal, coagulant, vermifuge, antidiarrheal, and astringent: and for healing wounds, managing obesity and diabetes, and maintaining oral hygiene (Stohs & Bagchi 2015). These are traditional indications, not clinical proof.

What modern research says

Knee osteoarthritis (human trials — combination products only)

Every recent human trial identified tested khadira only in combination with Chinese skullcap (Scutellaria baicalensis), never alone. (The review also notes an earlier small human study in lepromatous leprosy: a different product and era of research.)

The combination-product trials:

Because skullcap was in every tested product, these results cannot be credited to khadira alone. (Disclosure: the 2015 review's authors were affiliated with AdvoCare International, a supplement company: the usual caution about industry ties applies.)

Blood sugar, inflammation, and other effects (animal studies)

An ethyl acetate heartwood extract at 250 and 500 mg/kg lowered blood sugar in alloxan-induced diabetic rats, and an ethanolic bark extract showed antihyperglycemic activity in diabetic rats. The same extract showed antidiarrheal, antipyretic, and liver-protective effects in rats (Stohs & Bagchi 2015). Antioxidant activity is described as well established in vitro and in vivo, with anti-inflammatory, tissue-protectant, and analgesic activities demonstrated in animal and cell-culture systems (same review). Animal findings do not establish human efficacy.

What the evidence does not support (yet)

Standalone khadira, the heartwood or katha as traditionally used, has essentially no human efficacy data. The reviewers conclude there is "a need for additional human clinical studies with regard to efficacy and safety" (Stohs & Bagchi 2015). Traditional claims for diabetes, obesity, wounds, and skin disease remain untested in people.

Dosage

There is no established dose for khadira itself. The research regimens above used combination products, not khadira alone: flavocoxid 250 mg twice daily (12-week safety trial) and 500 mg twice daily (12-week efficacy trial versus naproxen), and UP446 500 mg/day (1-week trial): each a proprietary blend of A. catechu with Chinese skullcap (Stohs & Bagchi 2015). These are research doses of specific products, not personal recommendations, and they say nothing about traditional katha dosing.

Safety & contraindications

The review reports that "no adverse effects have been observed in animal or human studies or in cell culture systems," while noting that few human studies have ever been conducted and that the general safety of catechins and epicatechins is well documented (Stohs & Bagchi 2015). In the head-to-head trial, the khadira-containing blend showed better gastrointestinal, renal, and respiratory safety than naproxen (Levy et al. 2010, via Stohs & Bagchi 2015). That reassuring picture comes from short controlled trials. Postmarketing experience with the flavocoxid blend was different: four women developed clinically significant liver injury within 1–3 months of use (causality judged highly likely in three and possible in one; all recovered after stopping) (Chalasani et al. 2012; LiverTox). Postmarketing surveillance also documented hypersensitivity pneumonitis (a serious lung reaction). Between 2007 and 2017 the FDA received 30 adverse-event reports of elevated liver tests or acute hypersensitivity pneumonitis, and the FDA requested a market recall of flavocoxid in December 2017 (comparative safety analysis). These risks attach to the flavocoxid combination product, not to standalone khadira: but long-term standalone safety of khadira/katha in humans is unstudied. Treat it as an incompletely characterized herb and consult a qualified practitioner before use, especially if pregnant, breastfeeding, or taking prescription medicines.

FAQs

What is khadira / katha?

Khadira is Acacia catechu, a tree whose heartwood is boiled down into a tannin-rich extract called katha (catechu): mostly the polyphenols catechin and epicatechin (Stohs & Bagchi 2015). In Ayurveda it is a classic remedy for skin disorders, formulated for example as Khadirarishta (JAIMS 2025).

Does khadira help arthritis?

The only human data come from combination products blending A. catechu with Chinese skullcap: one 12-week trial (n=220) found the blend as effective as naproxen for knee-osteoarthritis symptoms with a better GI/renal safety profile (Levy et al. 2010, via Stohs & Bagchi 2015). Khadira alone has not been tested in people.

Is khadira safe?

No adverse effects were observed in the short animal and human studies reviewed, and the blend compared favorably with naproxen in a 12-week trial (Stohs & Bagchi 2015). But postmarketing reports later linked the flavocoxid combination product to rare liver injury and hypersensitivity pneumonitis, leading to an FDA-requested market recall in 2017 (PMC9704801). Standalone long-term safety of khadira itself is unstudied.

Can khadira be used for diabetes?

Animal studies show blood-sugar-lowering effects of heartwood and bark extracts in diabetic rats (Stohs & Bagchi 2015). No human trials support this: it is not a basis for managing diabetes.

Sources

Disclaimer

This article is for educational purposes only and is not medical advice. Herbal products can interact with medications and are not suitable for everyone. Talk to a qualified healthcare practitioner before use — especially if you are pregnant, breastfeeding, managing a medical condition, or taking prescription medicines.