Curry Leaves Side Effects: What a 2025 Toxicity Study Shows

Do curry leaves (Murraya koenigii, kadi patta) cause side effects beyond their already-known effect on blood sugar? A toxicology study published in 2025 offers new insight, this time on the liver and kidneys, from a concentrated extract tested at a single high dose in animals. For general uses and tolerance, see curry leaves; for the already-documented blood-sugar-lowering effect, see curry leaves dangers.

What the 2025 acute toxicity study shows

A study by Pinto, Alva, Gowda and Cojandaraj, published in 2025 in Toxicology International (vol. 32, no. 1, pp. 35-47), assessed the acute toxicity of a chloroform extract of Murraya koenigii leaves in female Wistar rats, at a single dose of 200 mg/kg and then 2,000 mg/kg (available on Google Scholar). At both doses, no significant change in body weight or in biochemical and hematological parameters was observed — a broadly reassuring signal. The authors conclude that the lethal dose 50 (LD50) lies above 2,000 mg/kg, a figure that reflects a wide safety margin for a single dose.

The more nuanced finding comes from histopathological examination: at the highest dose (2,000 mg/kg), the researchers noted lymphocytic infiltration in the liver and mild kidney edema — subtle tissue changes, absent at the lower dose of 200 mg/kg. In other words, even without measurable general toxicity in the blood, very concentrated doses can leave a microscopic trace on these two organs.

What this means concretely for human use

Form	Comparison with tested doses	Level of caution
Fresh leaves in cooking (tempering, chutney)	Far lower, nowhere near 2,000 mg/kg of extract	Low: well-tolerated daily traditional use
Occasional infusion or decoction	Clearly below the tested dose	Moderate: no warning signal identified
Concentrated extract, standardized powder, capsules	Depending on concentration, may approach it with repeated, prolonged use	High: caution advised, medical advice recommended if unsure

A pinch of leaves tossed into hot oil remains far removed from the bolus doses tested in this study, which moreover examined a single dose rather than repeated long-term use. But the study is a useful reminder for any herb: the safety of a food eaten at traditional doses doesn't automatically carry over to a standardized extract taken as a course, particularly when no repeated-dose toxicity data over several weeks exists for the exact commercial form purchased.

Liver and kidneys: a signal to watch, not a major alarm

The liver lymphocytic infiltration and kidney edema noted in this study are subtle changes, observed only at the highest dose tested, with no reflection in the usual blood markers (transaminases, creatinine). This is not proof of clear liver or kidney toxicity, but it's a sufficient reason to avoid prolonged high-dose courses of concentrated extracts without professional advice, particularly for people with a known liver or kidney weakness.

And the effect on blood sugar?

This new toxicological signal adds to, without replacing, the point of caution already identified in curry leaves dangers: a possible additive blood-sugar-lowering effect in people on antidiabetic treatment. Our Ayurveda and diabetes guide explains why this kind of preliminary literature should be read with caution, never replacing medical follow-up.

Pregnancy and sensitive populations

This study didn't test pregnant animals, but it reinforces the logic already set out in curry leaves and pregnancy: reserve ordinary culinary use, which raises no identified concern, and avoid concentrated extracts as a precaution given the lack of complete long-term safety data for this population.

Warning signs

• Unusual pain or discomfort near the liver (right upper abdomen) after a course of concentrated extract;
• Unusually dark urine, swelling in the legs or hands, which may signal kidney involvement;
• Faintness or signs of low blood sugar in someone on treated diabetes;
• Persistent digestive discomfort despite a moderate dose.

In these cases, stop taking it and see a doctor, especially if you're on chronic treatment or have a pre-existing liver or kidney condition.

Precautions

At ordinary culinary doses, curry leaf remains one of the best-tolerated ingredients in Indian cooking. Caution applies to concentrated extracts taken as a course: the safety margin observed at a single dose remains wide (LD50 above 2,000 mg/kg), but subtle liver and kidney changes at high dose call for not prolonging such courses without professional advice, particularly with diabetes treatment, pregnancy, or a known liver or kidney weakness. See our safety and precautions guide.