Male rats fed freeze-dried, skinned
(filetted)A. veraleaf at 1% of the diet showed
significantly fewer instances of death from
disease.^36 Oil-in-water aloe extracts signifi-
cantly increase soluble collagen levels, sug-
gesting a topical antiaging effect.^37 Dermal
wound-healing effects of oral and topicalA.
veragel in rats are partly attributed to their
ability to increase the contents of proteogly-
cans and glycosaminoglycans in the wound
matrix.^38
A systematic review of controlled clinical
trials on aloe vera preparations up to 1999
concluded that it is not clear whetherA. vera
promotes wound healing and that overall,
either topical or oral effectiveness of its pre-
parations remained insufficiently defined;
however, evidence suggested that it might be
effective in the treatment of psoriasis, genital
herpes, as an adjunctive in the management of
diabetes, and in lowering cholesterol levels.^39
A further critical review of clinical trials onA.
verapreparations in the treatment of various
dermatologic conditions up to 2000 concluded
that evidence for its efficacy remained
unconvincing.^40
TOXICOLOGY
Overdosage of drug aloe fluid and electrolyte
imbalance, abdominal pain, bloody diarrhea,
hemorrhagic gastritis, and sometimes nephri-
tis (BLUMENTHAL1;GOSSELIN;MARTINDALE), the
latter also associated in case studies with
prolonged use of Cape aloes containing aloe-
sin and aloeresin A.^41
No severe pathology was evident in mice
fed dry aloe extract (50 mg/kg).^42 Aloe is not
to be used for longer than 8–14 days; contra-
indicated for use by children of age 12 years
and under and in pregnancy, breast feeding,
menstruation, metrorrhagia, menorrhagia, ac-
tive hemorrhoids, diarrhea, intestinal ob-
struction or inflammation, inflammatory
bowel disease, kidney disease, vomiting, ap-
pendicitis, and abdominal pain. Use may
temporarily color the urine red. Toxic con-
stituents include aloeresin A and anthraqui-
none glycosides (aloinosides A and B and
aloins A and B) not found in A. veragel
(BLUMENTHAL1;BRINKER).^42 Use with other
laxatives, especially those containing anthra-
quinone glycosides (e.g., cascara, senna)
should be avoided owing to potentiating
effects.41,42Aloe is potassium-depleting. Use
with diuretics could or other potassium-de-
pleting substances (e.g., licorice root, thia-
zide diuretics, corticoadrenal steroids) could
result in hypokalemia.
Aloe veragel (freeze-dried) produced no
toxic effects in rats from either acute or
sub-chronic oral doses (1–64 mg/kg p.o.
twice daily). In mice or rats, the preserved
or fresh gel failed to cause any toxicity at
doses up to 20 g/kg p.o. or i.p., and no toxic
effects were found from a dose of 5 g/kg
p.o. per day for 45 days.^43 Life-long dosing
of a freeze-dried filet of the leaves at 1% of
the diet also failed to produce any deleteri-
ous effects.^36
Reported adverse effects of topical use of
A. veragel preparations by humans include
allergic contact dermatitis, mild itching, and
burning sensation. These effects have been
mild, of rare occurrence, and reversible when
use was stopped.17,44,45USESMedicinal, Pharmaceutical, and Cosmetic.
Currently the only officially recognized use
of aloe is as an ingredient in compound ben-
zoin tincture, presumably for its beneficial
properties on the skin.
Aloe and aloin are extensively used as
active ingredients in laxative preparations,
often with other cathartics such as buckthorn,
cascara, and senna; belladonna extracts are
often included to lessen griping. Aloin is also
used in antiobesity preparations.
In Germany, concentrated dried aloe leaf
juice is used for conditions in which ease of
defecation and soft stool are desired, for ex-
ample, anal fissures, hemorrhoids, postanor-26 Aloe (and aloe vera)