Benefits
Upper digestive comfort after meals
In a placebo-controlled trial of 148 adults with recurring upper digestive discomfort (functional dyspepsia), 350 mg three times daily for 3 weeks lowered symptom scores more than placebo; 77% vs 40% reported marked improvement, including less stomach pain and heartburn. A smaller crossover trial (1.4 g/day for 4 weeks) also found symptom improvement, but against a no-treatment period, not a placebo.
Digestive symptom scores alongside prescribed antibiotic therapy
In a single-blind pilot trial of 64 adults receiving standard four-drug therapy for H. pylori, clearance was 85% with added mastic gum vs 67% without, a difference that was not statistically significant. Symptom scores fell in both groups and somewhat more with mastic. This tested mastic as an add-on to prescribed drugs, not as a treatment on its own.
Taken alone, it did not match standard care for a stomach bacterium
Mastic kills H. pylori in the lab, but results in people are weak. Taken alone for 14 days, it cleared the infection in 4 of 13 and 5 of 13 people, versus 10 of 13 on standard antibiotics; in another study, 4 g a day for 14 days left all 8 completers infected, with no change in bacterial load. It is not a substitute for medical treatment.
Total cholesterol and fasting glucose markers
In an 8-week randomized pilot trial of 179 adults (156 analyzed) with total cholesterol above 200 mg/dl, 1 g/day of crude mastic lowered total cholesterol by about 11.5 mg/dl and fasting glucose by about 4.5 mg/dl. A 2 g/day powder and a polymer-free form showed no significant change, LDL, HDL and triglycerides did not change, and the placebo group had only 23 people.
Mouth bacteria and plaque when chewed as a gum
In 20 healthy dental students, chewing mastic gum lowered bacterial counts in saliva over 4 hours compared with a placebo gum, and over 7 days without brushing, plaque and gum-inflammation scores were lower with mastic gum than with placebo gum. Two small Turkish studies found fewer Streptococcus mutans in saliva for about 2 hours after chewing. None measured cavities.
Mechanism of action
Triterpenic acids with antibacterial activity in the lab
The acidic fraction of mastic, rich in triterpenic acids such as isomasticadienolic acid, was the most active part against 11 clinical H. pylori strains in vitro. In infected mice, a polymer-free extract cut colonization about 30-fold over 3 months but did not reduce stomach inflammation, and in another mouse study whole mastic cleared no infections.
Resin acids are absorbed into the blood
In a 3-month human trial, blood levels of masticadienonic and isomasticadienonic acid rose with the mastic dose (1.5 or 2.8 g/day), confirming that these triterpenic acids are absorbed when mastic is swallowed.
Local contact in the mouth when chewed
Chewing keeps the resin in contact with saliva and tooth surfaces, which is how the oral studies were run. Lab tests in the same work showed mastic extracts inhibiting Streptococcus mutans growth. Swallowed capsules or powder, used in the digestive trials, do not give this oral contact.
Clinical trials
Prospective, randomized, double-blind, placebo-controlled trial at a hospital on Chios, Greece; mastic gum 350 mg three times daily for 3 weeks. (Dabos et al. 2010, J Ethnopharmacol)
148 adults meeting Rome II criteria for functional dyspepsia.
Hong Kong dyspepsia index scores after treatment were lower with mastic than placebo (14.78 vs 19.96, p<0.05), and 77% vs 40% reported marked improvement (p<0.02). Stomach pain, stomach pain when anxious, dull upper abdominal ache and heartburn improved significantly. Run by a hospital team on the island where mastic is produced.
Randomized three-way crossover trial in Athens: four weeks each of Mastiha capsules (1.4 g/day), Mastiha water (20 ml/day) and no intervention, with 14-day washouts; registered as NCT05687539, which lists 48 enrolled. (Kleftaki et al. 2025, Pharmacol Res)
Adults with functional dyspepsia diagnosed by Rome IV criteria.
Both capsules and Mastiha water improved Leuven Postprandial Distress Scale scores compared with the no-intervention period (p<0.001). Capsules reduced upper abdominal bloating, epigastric burning and heartburn; Mastiha water improved quality of life (p=0.012). The comparison was against no treatment rather than a placebo, so expectation effects cannot be ruled out.
Randomized pilot study of mastic gum alone, mastic with pantoprazole, or standard triple therapy, with clearance checked by urea breath test 5 weeks after treatment. (Dabos et al. 2010, Phytomedicine)
52 patients with H. pylori infection confirmed by breath test; 13 per group.
Clearance occurred in 4 of 13 on 350 mg three times daily and 5 of 13 on 1.05 g three times daily, in none of 13 on mastic plus pantoprazole, and in 10 of 13 on pantoprazole, amoxicillin and clarithromycin. Breath-test values did not change significantly with any mastic regimen (trends p=0.08 and p=0.064). Mastic was well tolerated.
Uncontrolled study in Nottingham, UK; mastic 1 g four times daily for 14 days with urea breath tests before and after. (Bebb et al. 2003, J Antimicrob Chemother)
9 patients with H. pylori infection and no ulcer; 8 completed.
Mastic had no effect on H. pylori status in any of the 8 completers: all remained positive, and breath-test scores did not change (19.1 before vs 18.7 after, p=0.8). The authors concluded that despite activity in the lab, mastic had no effect on H. pylori in people.
Single-blind randomized pilot trial at AIIMS Rishikesh, India, of two weeks of standard bismuth quadruple therapy with or without mastic gum; the abstract does not state the mastic dose. (Tulsian et al. 2026, Indian J Gastroenterol)
64 adults with H. pylori infection (32 per group).
Clearance by breath test 6 weeks after therapy was 85% with mastic vs 67% without, which missed statistical significance (p=0.19), so the primary endpoint was not met. Dyspepsia symptom scores fell in both groups, with greater improvement in the mastic group (p=0.001). Both regimens were well tolerated.
Prospective, randomized, placebo-controlled pilot study at a hospital on Chios comparing crude mastic, polymer-free mastic and mastic powder for 8 weeks. (Kartalis et al. 2016, Eur J Prev Cardiol)
179 volunteers with total cholesterol above 200 mg/dl randomized; 156 analyzed (placebo 23, crude mastic 1 g/day 72, polymer-free mastic 1 g/day 33, mastic powder 2 g/day 28).
Crude mastic at 1 g/day lowered total cholesterol by 11.5 mg/dl and fasting glucose by 4.5 mg/dl (both p<0.05, adjusted), more so in people with BMI above 25. Polymer-free mastic and the 2 g/day powder produced no significant change. LDL, HDL, triglycerides and CRP did not change. No stomach, liver or kidney side effects were recorded.
Two double-blind randomized comparisons of mastic chewing gum vs placebo gum in Japan. (Takahashi et al. 2003, J Periodontol)
20 systemically and periodontally healthy dental students (the abstract gives n = 10 for the 7-day plaque comparison).
Bacterial colony counts in saliva were lower over 4 hours of chewing mastic gum than placebo gum (p<0.05). Over 7 days without toothbrushing, the mastic group had a lower plaque index (2.69 vs 3.15, p=0.001) and gingival index (0.44 vs 0.66, p=0.021). A small, short study of plaque and gum-inflammation scores, not cavities.