Does mastic gum kill H. pylori and protect the stomach?

Mastic gum contains a complex mixture of triterpenoids, diterpene acids, and volatile oils. The most potent antibacterial fraction appears to be the acidic resin component, with a compound called isomasticadienolic acid identified as particularly active against H. pylori³.

Against H. pylori: In vitro work shows mastic kills H. pylori at relatively low concentrations — in one study of clinical isolates, 50% of strains were killed at 125 µg/ml and 90% at 500 µg/ml⁹, and in another the most active extract fraction, the acid fraction, had a minimum bactericidal concentration (MBC) of 0.14 mg/ml³. In a mouse model, oral mastic reduced H. pylori colonization in stomach tissue by approximately 30-fold compared to untreated controls³. Human clinical trials have shown more modest results: as monotherapy, mastic eradicated H. pylori in about 31–38% of patients depending on dose in one randomized pilot². Standard antibiotic triple therapy achieves 70–80% eradication, so mastic alone should not be used as the sole treatment for confirmed H. pylori infection.

Stomach lining protection: Separate from its antibacterial activity, mastic appears to protect the gastric mucosa through what researchers call adaptive cytoprotection — it stimulates local prostaglandin production, which in turn strengthens the stomach's protective mucus layer. Animal studies using multiple ulcer models (aspirin-induced, stress-induced, pyloric ligation) consistently show reduced gastric damage with oral mastic at 500 mg/kg⁴. Notably, the protective effect is lost when prostaglandin synthesis is blocked, suggesting this is a key mechanism.

Anti-inflammatory effects: Mastic suppresses inflammatory signaling in gut tissue and endothelial cells. In human aortic endothelial cells, mastic extract and its isolated compound tirucallol significantly reduced expression of VCAM-1 and ICAM-1 — adhesion molecules that promote arterial inflammation — and attenuated NF-κB activation, a central driver of inflammatory responses⁶.

Practical dosing: Research studies have used a wide range of doses. For H. pylori: 350 mg to 1,050 mg three times daily for two weeks². For cardiovascular and metabolic effects: 5 g daily of mastic powder over 12–18 months⁵. Most commercial supplements provide 500 mg–1,000 mg per capsule. Traditional use typically involved chewing the raw resin, which delivers it directly to the upper GI tract.

Using mastic for gut health: Mastic works through local contact in the GI tract — it needs to actually reach and coat the stomach and intestinal lining. This is why intraperitoneal (injected) administration in animal studies showed no protective effect⁴. Take it before or with food for upper GI conditions, and consider chewable forms or opening capsules for best mucosal contact. For confirmed H. pylori, always work with a doctor; mastic may be useful as adjunct support during or after antibiotic treatment.

See our leaky gut page for related information on repairing the intestinal lining.

H. pylori: from in vitro to clinical trials

The modern scientific interest in mastic gum began with a 1998 letter in the New England Journal of Medicine by Huwez et al., reporting that mastic gum kills H. pylori — a striking finding given the bacterium's role in peptic ulcers¹. Subsequent in vitro work by Marone et al. (2001)⁹ confirmed bactericidal activity against clinical H. pylori isolates (50% of strains killed at 125 µg/ml and 90% at 500 µg/ml), and transmission electron microscopy showed that sub-bactericidal concentrations caused blebbing, morphological abnormalities, and cellular fragmentation in H. pylori cells. Paraschos et al. (2007) refined this further, identifying isomasticadienolic acid as a key active constituent and demonstrating ~30-fold reduction in H. pylori colony counts in a mouse gastric infection model after 3 months of treatment³.

However, clinical translation has been inconsistent. Dabos et al. (2010) conducted a randomized pilot (n=52) comparing four groups: low-dose mastic alone (350 mg three times daily), high-dose mastic alone (1,050 mg three times daily), low-dose mastic plus pantoprazole, and standard triple therapy². Eradication rates for mastic monotherapy were 31% (low dose) and 38% (high dose), compared to 77% for standard triple therapy. Unexpectedly, combining mastic with pantoprazole resulted in 0% eradication — the authors speculate the proton pump inhibitor may interfere with mastic's mechanism. Bebb et al. (2003) reported a negative result using 1 g four times daily for 14 days: all 8 patients who completed treatment remained H. pylori positive, with no change in ¹³C urea breath test scores, although the study was very small⁷.

The most recent trial (Tulsian et al., 2026) was a single-blind, randomized pilot that tested mastic as an adjunct to two weeks of bismuth quadruple therapy in 64 patients (32 per group). Eradication, measured by urea breath test six weeks after treatment, was 85% with mastic added and 67% with quadruple therapy alone, an 18-point difference that was not statistically significant (p = 0.19), so the trial missed its primary endpoint. Dyspepsia symptoms improved significantly more in the mastic group (p = 0.001), and both regimens were well tolerated⁸. Overall: laboratory and animal evidence is encouraging, but clinical data are limited and mixed — mastic alone did not clear the infection in the small studies above, and as an adjunct it eased symptoms more without a statistically significant gain in eradication.

Gastric mucosal protection

Al-Said et al. (1986) conducted a systematic evaluation of mastic across six different ulcer induction models in rats⁴. Oral mastic at 500 mg/kg produced significant cytoprotection in all models tested: pyloric ligation-induced ulcers, aspirin-induced damage, phenylbutazone, reserpine, restraint/cold stress, and cysteamine-induced duodenal ulcers. Two mechanistic findings were notable: (1) pretreatment with indomethacin abolished the protective effect against ethanol-induced damage, implicating prostaglandin-mediated cytoprotection; (2) intraperitoneal administration showed no protection, indicating that direct mucosal contact is required. The resin also reduced free acidity in pylorus-ligated rats, suggesting a mild antisecretory component. While rat ulcer models have well-known translational limitations, the consistency across six different injury models strengthens the evidence for genuine cytoprotective activity.

Cardiovascular and metabolic effects

Triantafyllou et al. (2007) randomized 133 adults over 50 years of age to either high-dose mastic powder (5 g/day for 18 months) or a low-dose mastic solution (12 months)⁵. In the high-dose group, significant reductions were observed in total cholesterol, LDL cholesterol, total cholesterol-to-HDL ratio, lipoprotein(a), and the apolipoproteins apoA-1 and apoB. Liver enzyme markers — SGOT, SGPT, and gamma-GT — also declined, suggesting hepatoprotective activity. The low-dose group showed glucose reductions specifically in male participants. Effect sizes were not reported in detail, and the study lacked a true placebo arm for the high-dose group, which limits interpretation. Still, this remains the largest and longest human trial of mastic gum's metabolic effects.

Anti-inflammatory mechanism

Loizou et al. (2009) investigated mastic's anti-inflammatory effects in human aortic endothelial cells treated with TNF-α to simulate vascular inflammation⁶. Both crude mastic extract (25–200 µg/ml) and the isolated compound tirucallol (0.1–100 µM) dose-dependently reduced VCAM-1 and ICAM-1 expression — cell-surface adhesion molecules that facilitate monocyte recruitment, an early step in atherosclerotic plaque formation. Monocyte adhesion to activated endothelial cells was correspondingly reduced. The mechanism involved attenuated phosphorylation of NF-κB p65. This molecular data complements the human lipid trial and suggests mastic may act on multiple cardiovascular risk pathways simultaneously.

Strength of evidence summary

The totality of evidence supports mastic gum's role as a gastric-protective and mildly antibacterial agent with additional anti-inflammatory properties. The H. pylori data is compelling mechanistically but inconsistent clinically — monotherapy achieves 31–38% eradication in the most favorable trial, which is insufficient as sole treatment for active infection. Gastric cytoprotection is well-supported in animal models through a plausible prostaglandin-dependent mechanism. The human cardiovascular trial (n=133) provides the strongest clinical evidence for systemic benefits, though it requires replication with better controls. No serious safety concerns have emerged across trials at doses up to 5 g/day over 18 months.