Can liquorice be used to treat indigestion?
Q Does liquorice work for indigestion?
A Liquorice (Glycyrrhiza glaba) has expectorant, secreteolytic, antispasmodic, anti-inflammatory, adrenocorticotropic and aldosterone-like properties.
It is often contained in herbal preparations used for problems such as gastric ulcers, catarrhs, for cancer prevention, 'detoxification' and as an anti-inflammatory agent.
For none of these do we have sufficient trial data to confirm or refute efficacy. In fact, for most of the above conditions there are no randomised trials at all. Indigestion is no exception, and opinion is not a sound basis for recommendations.
This is particularly true for liquorice because of its unusually prominent adverse effects. Due to its pharmacology it can cause hypertension, sodium retention, oedema, lethargy, amenorrhoea and headache.
The dose for this to occur is around 50mg liquorice root per day. In addition, liquorice has been implicated in interactions with prescribed drugs including NSAIDs, antihypertensives, aspirin, corticosteroids, cardiac glycosides, cimetidine, diuretics, hormones and MAO-inhibitors.
The roots of the liquorice plant are frequently used in Chinese herbal medicine. It is normally combined with several other herbal ingredients – one patient presenting with indigestion would most likely receive a different combination of herbs from the next suffering from similar problems.
So, does it work? Yes, liquorice has powerful pharmacological effects. It may even benefit patients with indigestion.
I doubt, however, whether it would be wise to use it for indigestion.
Edzard Ernst is professor of complementary medicine,
Peninsula Medical School, Exeter