Herb library · Herb · Syzygium cumini
Jamun (black plum)
The purple summer fruit of India, whose seed powder is one of the most sold folk remedies for blood sugar. In the one controlled trial of its leaf tea in people with diabetes, blood sugar did not change.
Traditional use
Dutt's 1877 compilation of the Sanskrit medical writers records that a vinegar of the ripe fruit was taken as a stomachic and for scanty urine, that the astringent bark was used in gargles and washes and, with goat's milk, for children's diarrhea, and that the leaf juice was given for dysentery. Across South Asia the fruit is eaten fresh in July and August, and the dried seed powder is widely sold and taken for blood sugar. Jambolan leaf tea is also a popular home remedy for diabetes in Brazil.
What studies show
- Limited· shows no benefit
Blood sugar (leaf tea): in a double-blind, randomized trial in Brazil, 27 people with type 2 diabetes drank jambolan leaf tea, took a standard diabetes drug, or took placebo for 28 days. Fasting blood sugar fell with the drug and did not change with the tea.
- Insufficient
Seed powder and fruit: no well-designed trial of jamun seed or fruit on its own was found. A 2026 review that reported a small drop in fasting blood sugar pooled jamun with other plants of the myrtle family.
Be careful of
Cautions
- InteractionIf you take medicine for diabetes, do not swap it for jamun seed powder. Check your blood sugar and tell your clinician if you add any herb that is used to lower it.
- PregnancyThe fruit is an ordinary food. No safety information for concentrated seed powder or extracts in pregnancy or breastfeeding was found.
- Ask a clinicianTalk with a clinician or pharmacist before using jamun seed powder or extracts if you take prescription medicines, are pregnant or breastfeeding, or are giving them to a child.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“A vinegar prepared from the juice of the ripe fruit, is an agreable stomachic and carminative. It is also used as a diuretic in scanty or suppressed urine.”
Sources
- The efficacy of folk medicines in the management of type 2 diabetes mellitus: results of a randomized controlled trial of Syzygium cumini (L.) Skeels (J Clin Pharm Ther, 2006) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
- Efficacy and Safety of Syzygium cumini and Related Myrtaceae Interventions for Dysglycemia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials (Foods, 2026) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
Reviewed September 25, 2026.