Curcuma longa

Kunyit is the kitchen's botanical before it is the healer's: the rhizome
colours and seasons the everyday Malay table, and the same fresh-pounded
paste appears in the region's body-care tradition — most visibly in the
postpartum param, the warming paste applied during confinement. Jamal and
colleagues' 2011 survey of Malay traditional practitioners in Peninsular
Malaysia records Curcuma longa among the most frequently used species in
postnatal care, including topical preparations [1]. The wider Javanese jamu
tradition uses turmeric species in comparable mixtures, documented for
Curcuma xanthorrhiza (temulawak) alongside C. longa [2] — corroborating
context for the practice rather than evidence for this species alone.

The rhizome's colour and most of its studied pharmacology belong to the
curcuminoids — curcumin, demethoxycurcumin and bisdemethoxycurcumin — with
a volatile oil fraction dominated by sesquiterpenes such as ar-turmerone
[3]. Curcumin's poor oral bioavailability is one of the field's central
complications: the clinical trials below used standardised extracts at
gram-per-day doses, and their results cannot be assumed to transfer to
culinary quantities — or across the skin from a paste.

The clinical evidence sits with the oral extract. Kuptniratsaikul and
colleagues (2009) randomised 107 patients with knee osteoarthritis to
Curcuma domestica (= C. longa) extract at 2 g/day or ibuprofen for six
weeks and reported similar improvement in both arms [4]. The same group's
2014 multicentre trial (n=367) found the extract at 1,500 mg/day
non-inferior to ibuprofen on WOMAC scores over four weeks, with fewer
gastrointestinal complaints [5]. Daily and colleagues' 2016 meta-analysis
of randomised trials concluded that around 1,000 mg/day of curcumin
relieved arthritis symptoms, while stating that the number and quality of
trials was insufficient for definitive conclusions [6].

That last sentence is why this entry is B rather than A — and one caveat
matters more than any of it: the traditional preparation this monograph
describes is a warming paste on the skin, and no randomised trial of a
topical param-style preparation has been published. The oral evidence
establishes that the plant's chemistry is clinically interesting; it does
not validate the traditional format.

Since that meta-analysis the picture has been refined rather than
overturned. A dose-stratified meta-analysis of eleven randomised trials
(n=1,258) examined high- and low-dose curcumin against pain and function
scores [8]; a Bayesian network meta-analysis compared curcuminoid
formulations with NSAIDs and placebo [9]; and a 2025 network meta-analysis
ranked turmeric preparations for knee osteoarthritis [10]. A 2025 umbrella
appraisal of these reviews is candid that their methodological quality
varies [11]. None of this changes the central caveat: every trial used oral
extract at gram doses, and the traditional preparation described above is a
paste on the skin.

Turmeric has an exceptionally long record of dietary use. The Soleimani
2018 safety review reports oral curcumin tolerated at doses up to 6 g/day
over several weeks in human studies, with gastrointestinal upset the main
complaint [7]. On skin, fresh turmeric paste stains and can irritate
sensitised individuals; patch-test before applying a concentrated
preparation. High-dose extracts are best avoided in pregnancy and alongside
anticoagulant medication without professional advice, and gallbladder
disease is a recorded caution for concentrated oral extract.

One signal has strengthened since the older safety reviews and belongs in
any current assessment. The US Drug-Induced Liver Injury Network published
ten adjudicated cases of turmeric-associated liver injury, with the
HLA-B*35:01 allele identified as a susceptibility marker [12]. A
subsequent United States Pharmacopeia expert review concluded such cases
are rare and related to dose and to enhanced-bioavailability formulations,
while recommending a cautionary statement in the monograph [13]. The
practical reading: culinary kunyit and topical paste are not the concern;
concentrated high-bioavailability oral supplements are. Malaysian
hospital-based work has separately flagged peripartum herbal ingestion as
warranting clinical attention [14].