Aloe vera

The split leaf of Aloe vera, applied gel-side down to scalds and sunned
skin, is one of the most widely recorded pieces of domestic plant knowledge
in the tropics, and the Malay name — lidah buaya, "crocodile's tongue" —
attests to how thoroughly the plant has been absorbed into household use in
the region. Grindlay and Reynolds' 1986 review traces the documented history
of the leaf gel across folk traditions, and notes the long-standing
distinction practitioners draw between the soothing inner gel and the
bitter yellow latex beneath the rind [1]. Malay village herbal practice has
been formally surveyed — Ong and Nordiana's 1999 ethnobotanical study in
Machang, Kelantan records a living tradition of over a hundred medicinal
species in domestic use [2] — though species-level documentation of aloe in
Malay-world surveys remains thinner than its ubiquity in gardens suggests.

The inner gel is over 98% water; its characteristic constituents are
polysaccharides, principally acemannan and related glucomannans, alongside
glycoproteins, amino acids and trace sterols [3]. Acemannan — a partially
acetylated β-(1→4)-mannan — is the constituent most studied in relation to
skin repair, and a 2019 review assembles the extraction, characterisation
and laboratory data around it [4]. The yellow latex from the pericyclic
cells is chemically distinct: it carries anthraquinones (aloin A and B)
with strong laxative action, and does not belong in topical preparations.
Commercial gels are rarely assayed for polysaccharide content, which
complicates comparison between studies.

The clinical literature on aloe and burns is real but thin. A 2007
systematic review by Maenthaisong and colleagues identified four controlled
trials (n=371) of aloe preparations for first- and second-degree burns and
pooled a healing-time advantage of roughly nine days over comparator
dressings — while stating plainly that the included studies were few, small
and methodologically weak [5].

The individual trials behind that pooling are instructive. Visuthikosol and
colleagues (1995) compared aloe gel with vaseline gauze in 27 patients with
partial-thickness burns and reported healing at 11.9 versus 18.2 days, with
supporting histology [6]. Khorasani and colleagues (2009) ran a
within-patient comparison of an aloe cream against silver sulfadiazine on
paired burn sites in 30 patients and reported re-epithelialisation at 15.9
versus 18.7 days [7]. Both are small, unblinded, single-centre studies, and
the preparations differ — fresh gel, cream, gel-impregnated gauze — so the
results cannot be attributed to any standardised product.

That is the shape of a grade B: human trials exist, they point in a
consistent direction for minor superficial burns, and none of them is
large, blinded or standardised enough to settle the question.

A second systematic review has since been published, this time from
Universiti Kebangsaan Malaysia: eleven controlled clinical trials from
2015 to 2022 of aloe gel and cream in pressure injuries, chronic ulcers
and diabetic foot ulcers [10]. A Malaysian-authored mechanistic review
addresses which constituents drive the proliferative phase of repair [11].
The direction of the literature has not changed — the trials remain small
and the preparations remain unstandardised — but the systematic-review
rung is now well established for this botanical.

Topical aloe gel is generally well tolerated on intact and superficially
injured skin. Allergic contact dermatitis is documented — patch-test
confirmed cases exist, including to home-made leaf preparations [8] — so a
patch test before first use is sensible, and use should stop if stinging or
rash develops. The Guo and Mei 2016 toxicology review distinguishes the
topical gel, with its low adverse-effect profile, from oral whole-leaf
extract, whose anthraquinone content carries laxative effects and separate
regulatory concern [9]. Deep, extensive or infected burns need clinical
care, not a plant preparation; this monograph concerns minor superficial
burns only. Data in pregnancy for topical use are limited.

A 2025 comprehensive review restates the distinction that matters most
here: topical gel is well tolerated, while prolonged intake of
anthraquinone-rich latex carries hepatotoxic and nephrotoxic risk [12].
That is a caution about the wrong part of the leaf taken the wrong way,
and it is precisely the separation the tradition already makes.