Oral supplementation with dimethyl sulfoxide (DMSO) reduces the relapse rates for peptic ulcer. DMSO in combination with cimetidine is more effective then cimetidine alone. Licorice may protect the stomach and duodenum by increasing production of mucin, a substance that protects the lining of these organs against stomach acid and other harmful substances. According to laboratory research, deglycryrrhizinated form of licorice may also provide a soothing of H. phlori and also provide a soothing effect. The gummy extract of pistachia lentiscus, also known as mastic or gum mastic, may heal peptic ulcers by its ability to kill H. pylori.