According to MedlinePlus and the Natural Medicines Comprehensive Database, licorice is "possibly effective" for dyspepsia in combination with other herbs, but there is "insufficient evidence" to rate its effectiveness for other conditions. Regarding stomach ulcers, specifically, there is "some evidence...that specially prepared licorice will speed the healing of stomach ulcers".
An un-blinded study of 82 patients from the early 1980s, published in the British Medical Journal, reported that Caved-S had a therapeutic effect similar to that of cimetidine in the treatment of gastric ulcers.
- Licorice: MedlinePlus Supplements, United States National Library of Medicine, National Institutes of Health
- Morgan AG, Pacsoo C, McAdam WA (June 1985). "Maintenance therapy: a two year comparison between Caved-S and cimetidine treatment in the prevention of symptomatic gastric ulcer recurrence". Gut 26 (6): 599–602. doi:10.1136/gut.26.6.599. PMC 1432764. PMID 4007604.
Morgan AG, McAdam WA, Pacsoo C, Darnborough A (June 1982). "Comparison between cimetidine and Caved-S in the treatment of gastric ulceration, and subsequent maintenance therapy". Gut 23 (6): 545–51. doi:10.1136/gut.23.6.545. PMC 1419696. PMID 7042486.