- Guava leaf is commonly used for gastrointestinal conditions, pain, diabetes, and wound healing. Guava fruit is used for hypertension. However, there is no strong evidence to support any of these uses.
- Guava fruit is likely safe when used orally in amounts found in foods and possibly safe when used as medicine. Guava leaf extract is possibly safe when used orally as medicine or when used topically. Guava leaf extract might irritate the skin.
- No known major interactions.
People Use This For
Topically, guava leaf is used for joint pain, gingivitis, oily skin, skin infections, fever, vaginal irritation and infection, wounds, ulcers, and boils. The bark and root are used for skin ailments. The flower bud is used for eye strain and eye infections. The unripe fruit is used for ulcers and wounds. The shoot is used for fever.
POSSIBLY SAFE …when guava fruit or leaf extract is used orally for medicinal purposes, short-term. Guava fruit has been used with apparent safety at doses of 500-1000 grams daily for 12 weeks (95562). Guava leaf extract has been used with apparent safety at doses of 1 gram daily for 12 weeks or 1.5 grams daily for 3 days (101758,70318). …when the leaf extract is used topically, short-term. Guava leaf extract has been used safely as a mouth rinse at a dose of 0.15% twice daily for 30 days (101754). Guava leaf extract has been safely used on the skin at a dose of 6% twice daily for 28 days (101757).
PREGNANCY AND LACTATION: LIKELY SAFE …when guava fruit is consumed as food. There is insufficient reliable information available about the safety of guava fruit or leaf when used for medicinal purposes during pregnancy and lactation.
Dysmenorrhea. Clinical research in young women with dysmenorrhea shows that taking guava leaf extract 1 mg or 2 mg three times daily for 5 days starting 24 hours before menstruation for 3 cycles does not reduce pain when compared with placebo. However, pain was reduced by a small amount in the women with the best compliance (101782).
Gingivitis. Clinical research in patients with moderate to severe chronic gingivitis shows that using a guava leaf extract 0.15% mouth rinse twice daily with brushing for 30 days is as effective as 0.2% chlorhexidine and more effective than water for reducing gingivitis severity and microbial counts. However, using the guava leaf extract mouth rinse does not appear to improve plaque (101754).
Hypertension. Preliminary clinical research in patients with essential hypertension shows that eating guava fruit 500-1000 grams daily in place of other foods high in saturated fat and cholesterol for 12 weeks lowers systolic blood pressure by 9.0 mmHg and diastolic blood pressure by 8.0 mmHg compared to usual diet (95562).
Knee pain. Preliminary clinical research in patients with knee pain shows that taking guava leaf extract 1 gram daily for 12 weeks reduces pain and stiffness by a small amount when compared to placebo. There is no effect on function (101758). This study was small and might not have been adequately powered to detect differences.
More evidence is needed to rate guava for these uses.
Dosing & Administration
Diarrhea: Guava leaf extract (QG-5) 500 mg every 8 hours for 3 days has been used (70318).
Hypertension: Guava fruit 500-1000 grams daily for 12 weeks has been used (95562).
Knee pain: Guava leaf extract 1 gram daily for 12 weeks has been used (101758).
Gingivitis: Guava leaf extract 0.15% as a mouth rinse twice daily with brushing for 30 days has been used (101754).
Standardization & Formulation
Interactions with Drugs
Theoretically, concomitant use with antidiabetes drugs might have additive effects and increase the risk of hypoglycemia. Animal research shows that guava leaf extract or guava fruit can have hypoglycemic effects (101781). Monitor blood glucose levels closely. Medication dose adjustments may be necessary.
Interactions with Herbs & Supplements
HERBS AND SUPPLEMENTS WITH HYPOGLYCEMIC POTENTIAL: Guava leaf extract or fruit might have hypoglycemic effects (101781). Theoretically, concomitant use with other herbs and supplements with hypoglycemic potential levels might increase the risk of hypoglycemia. Some of these herbs and supplements include ginger and others.
Interactions with Diseases
DIABETES: Guava might reduce blood glucose levels in patients with diabetes (101781). Monitor blood glucose levels closely. Doses of conventional antidiabetes medications may require adjustment.
SURGERY: Guava may reduce blood sugar levels (101781). Theoretically, guava might affect blood sugar control if used perioperatively. Tell patients to discontinue using guava at least 2 weeks before elective surgical procedures.
Mechanism of Action
General: The applicable parts of guava are the leaf and fruit. The flowers, root, bark, and stem are also used medicinally (95557,101781). The leaves contain the flavonoids quercetin, avicularin, guaijaverin. The leaves also contain tannin, apigenin, and other polyphenols, triterpenes, saponins, lectins, carotenoids, vitamin C, and fatty acids (14267,14270,95557,101758). Guava leaf essential oil contains cineol, limonene, eugenol, caryophyllene, pinene, and myrcene. The volatile constituents include cinnamic acid and hexenoic acid (14267,101781). The guava fruit contains vitamin C (14267,95560). The fruit pulp and peel contain about 49% fiber and about 3% to 8% polyphenols (14271). Guava bark and root are high in tannins (101781). The flower buds are rich in flavonoids (101781).
Anticancer effects: Guava leaf extracts have high polyphenol content and are thought to have anticancer effects (14267,95557). In vitro research has found that guava leaf extracts are cytotoxic against leukemia cells, oral cancer cells, and other cancers. Polyphenols such as apigenin and lycopene have antioxidant effects and scavenge free radicals helping to prevent the development of cancerous cells (14268,95557).
Antidiabetic effects: Guava leaf extract has shown hypoglycemic effects, possibly related to increased synthesis of liver glycogen (14267,101755). Guava fruit has also been shown to lower fasting blood glucose levels in an animal model. This effect has been attributed to the fiber content of the fruit (14276). Preliminary clinical research in healthy volunteers shows that eating 400 grams of ripe guava WITH peel daily for 6 weeks increases fasting blood glucose compared to baseline. On the other hand, eating guava 400 grams WITHOUT peel seems to decrease fasting blood glucose compared to baseline. The hypoglycemic effect of the guava WITHOUT peel is thought to be due to alpha-glucosidase inhibition in the intestine, which reduces glucose absorption (95559).
Cardiovascular effects: Research in healthy volunteers shows that eating 400 grams of ripe guava fruit daily for 6 weeks OR drinking 500 mL of guava fruit juice once is associated with reduced blood pressure compared to baseline (95559,95563). This reduction might be related to a reduction in weight in the 6 week study (95559). Additionally, guava leaf extract seems to have negative inotropic effects on animal cardiac tissue ex vivo which also helps explain guava’s blood pressure lowering effects (14267).
In healthy volunteers, consuming guava fruit WITH peel 400 grams/day for 4-6 weeks seems to increase total cholesterol, and triglycerides compared to baseline and control. However effects on high-density lipoprotein (HDL) cholesterol levels were mixed (14273,95559). On the other hand, eating guava 400 grams WITHOUT peel seems to decrease total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides, and increase HDL cholesterol compared to baseline (95559). Additionally, some research suggests that guava fruit lowers cholesterol at higher intake amounts and longer duration of intake.
There are a few theories as to why guava affects cholesterol levels. One theory is that the cholesterol lowering effects of guava are due to the soluble fiber, pectin, content of the guava pulp (95559). Another theory is that guava decreases cholesterol levels due to its antioxidant effects. Guava fruit pulp and peel extracts seem to have antioxidant activity and decrease LDL oxidation in vitro (14271,14272,14273). In animals, the leaf extract inhibits hormone sensitive lipase (101755).
Finally, in vitro, blood taken from healthy volunteers who drank 500 mL of guava fruit juice 10 minutes prior to giving blood demonstrates reduced collagen-induced platelet aggregation but not adenosine diphosphate-induced platelet aggregation compared to baseline (95563).
Gastrointestinal effects: Guava leaf extracts are thought to have antidiarrheal effects (14267,101781). In animal models, the guava leaf extract seems to decrease peristalsis in the intestine. This might be due to the flavonoid constituents such as quercetin. These constituents seem to decrease intracellular calcium release, which could result in decreased smooth muscle contraction (14267,14269).
Neurologic effects: Preliminary research in animal models suggests that guava leaf extracts have antinociceptive and CNS depressant effects (14267).
Respiratory effects: Preliminary research in animal models suggests that guava leaf extract has antitussive effects (14267).