The gentians have been used for centuries as bitters to stimulate the appetite, improve digestion, and treat a variety of gastrointestinal complaints. The medicinal components are derived from the roots and rhizome of G. lutea species and include the following: amarogentin, gentiopicrin, gentiopicroside, swertiamarin, the alkaloids gentianine and gentialutine, xanthones, carbohydrates, pectin, tannins, triterpenes, and volatile oils.

Both gentian and stemless gentian are approved for food use. Stemless gentian usually is consumed as a tea, or in alcoholic extracts such as Angostura Bitters. Gentian extracts are used in a variety of foods, cosmetics, and some antismoking products. The plant has been used externally to treat wounds and internally to treat sore throat, arthritic inflammations, and jaundice. Gentian may stimulate gastric secretions. Because it's usually administered with alcohol, it's difficult to determine whether the gentian or the alcohol is having the gastric effects. It's available as bitter tonic, dried powder, dried root, extract, tincture, and tea.

Reported uses

Gentian is used to stimulate appetite and to aid in digestion by stimulating gastric juices. It's also used to treat flatulence and feelings of fullness. Gentian may have some anti-inflammatory effects.

Administration

Dried rhizome or root: 2 to 4 g by mouth every day

Liquid extract 0:1 glml): 2 to 4 g by mouth every day (1 to 2 ml, two to three times daily, 1 hour before meals)

Tea: Steep 1 to 2 g ('h teaspoon) of the herb in boiling water for 5 to 10 minutes

Tincture: 0:5 in 45% alcohol) 1 to 4 ml by mouth three times a day; average dose is 1 to 3 g every day.

Hazards

Adverse reactions associated with gentian include headache, GI upset, nausea, and vomiting. There may be an increased sedative effect when administered with barbiturates or benzodiazepines because of the alcohol content in the liquid preparations. The potential for disulfiram-like reactions exists with cephalosporins, disulfiram, and metronidazole because of the alcohol content in the liquid preparations. Theoretical interaction with acid-inhibiting drugs (antacids, sucralfate, H-2 antagonists, proton pump inhibitors) is due to gentian's increase of stomach acid.

Patients with stomach or duodenal ulcers or excessive acid production (Zollinger Ellison Syndrome) shouldn't use. Pregnant and breast-feeding patients should also avoid use. Patients with hypertension should use with caution.

Clinical considerations

Tell patient to discontinue use if stomach upset occurs.

Advise patient that the tincture form contains alcohol.

Advise patient to keep product out of direct light.

Tell patient to remind pharmacist of any herbal or dietary supplement that he's taking when obtaining a new prescription.

Advise patient to consult his health care provider before using an herbal preparation because a conventional treatment with proven efficacy may be available.

Safety Risk Don't confuse gentian with gentian violet, also. known as crystal violet; they have different uses.

Research summary

Gentian is a widely recognized plant that has been used as a bitter tonic for centuries. It is believed that a small amount of the extract (usually mixed with alcohol) can stimulate appetite and improve digestion. Aside from this, none of the other effects is well documented in humans. Therefore, the concepts behind the use of gentian and the claims made regarding its effects haven't yet been validated scientifically.