of Ginger Trials Yields "Promising" Outcome
Throughout centuries of traditional use,
treatment of nausea and vomiting has remained one of the primary
therapeutic applications of ginger root (Zingiber officinale
Roscoe., Zingiberaceae). In order to "evaluate whether or not
ginger is truly efficacious for clinical nausea and vomiting,"
investigators Ernst and Pittler of Exeter University, U.K., reviewed
six randomized, controlled clinical trials that met standard methodological
quality criteria (Ernst and Pittler, 2000).
Only randomized, double-blind, placebo-controlled
trials evaluating the use of ginger as a single agent in the treatment
of nausea and vomiting were eligible for inclusion in the review.
(Studies assessing the effects of ginger on experimentally induced
nausea and/or vomiting were excluded.) The six studies chosen
investigated the use of ginger in four different areas: motion
sickness (Grøntved et al., 1988), morning sickness (Fischer-Rasmussen
et al., 1990), postoperative nausea (Bone et al.,
1990; Phillips et al., 1993; Arfeen et al., 1995)
and chemotherapy-induced nausea (Pace, 1987).
The majority of the trials reviewed concluded
that ginger powder taken at a dose of 1 g daily was significantly
more effective than placebo in alleviating nausea and vomiting.
The one exception was a postoperative nausea study by Arfeen and
colleagues, which demonstrated no significant difference between
ginger and placebo or between ginger doses of 0.5 g and 1 g. The
authors noted, "The discrepancy between this negative outcome
and the positive results from other RCT [randomized controlled
trials] is not readily explicable." No adverse events were reported
in any of the studies.
Noting that the body of literature on ginger
may be influenced by publication bias - i.e., a tendency among
researchers not to publish studies with negative outcomes - the
authors end on a cautionary note: "In summary, we found that ginger
is a promising antiemetic herbal remedy, but the clinical data
to date are insufficient to draw firm conclusions."
- Evelyn Leigh, Herb Research Foundation
[Arfeen Z, Owen H, Plummer JL, Ilsley AH, Sorby-Adams RAC,
Doecke LJ. A double-blind randomized controlled trial of ginger
for the prevention of postoperative nausea and vomiting. Anaesth
Intensive Care 1995; 23: 449-452. Bone ME, Wilkinson DJ, Young
JR, McNeil J, Charlton S. Ginger root-a new antiemetic: The effect
of ginger root on postoperative nausea and vomiting after major
gynaecological surgery. Anaesthesia 1990; 45: 669-671.
Ernst E, Pittler MH. Efficacy of ginger for nausea and vomiting:
a systematic review of randomized clinical trials. British
Journal of Anaesthesia 2000; 84(3): 367-371. Fischer-Rasmussen
W, Kjaer SK, Dahl C, Asping U. Ginger treatment of hyperemesis
gravidarum. Eur J Obstet Gynecol Reprod Biol 1990; 38:
19-24. Grøntved A, Brask T, Kambskard J, Hentzer E. Ginger root
against seasickness: a controlled trial on the open sea. Acta
Orolaryngol 1988; 105: 45-49. Pace JC. Oral ingestion of encapsulated
ginger and reported self-care actions for the relief of chemotherapy-associated
nausea and vomiting. Dissertations Abstracts Int 1987;
47: 3297-3298. Phillips S, Ruggier R, Hutchinson SE. Zingiber
officinale (Ginger) - an antiemetic for day case surgery.
Anaesthesia 1993; 48: 715-717.]