Dill (Anethum graveolens L.): A Comprehensive Reference
1. Identity, Taxonomy, and Botanical Description
Botanical name: Anethum graveolens L. Family: Apiaceae (Umbelliferae). Common synonyms: Dill, dillweed, dill seed. The plant is also listed in pharmacological references under the synonym Peucedanum graveolens and its essential oil under the name Oleum anethi.
Dill is a hardy, short-lived perennial herb native to the Mediterranean and southern Russia, and grows wild in Spain, Portugal, and Italy. It is cultivated in the Mediterranean region, central and eastern Europe, South Asia, and southeastern Iran.
The plant produces leaves (commonly called "dillweed"), fruits (commonly but imprecisely called "seeds"), and an essential oil distilled from either the fruit or leaf. The dried fruit, known as dill seeds, is used as a spice. The leaves, known as dill weed, are used fresh or dried as an herb. An essential oil from the fruit (dill seed oil) and leaf (dill leaf oil) is used in food flavoring, medicine, and perfuming soaps.
Common Preparations and Dosage Forms
- Fresh or dried leaves (dillweed): consumed through methods such as tea preparation and incorporation into soups and salads, relying on aqueous extraction techniques.
- Dried fruit/seed: dill seeds inherently contain a variable quantity of essential oil ranging between 2.5 to 3.5 per cent.
- Essential oil: Obtained by hydro-distillation from aerial parts or seeds; used in food, pharmaceutical, and cosmetic applications.
- Powdered seed/fruit capsules: used in clinical research, for example 3 g/day dill powder administered as 3 capsules/day (1 g each).
- Dill tablet: a commercial medicine prepared from Anethum graveolens L. (dill) is marketed as dill tablet (DT) as a hypolipidemic agent.
- Aqueous extract / infusion ("gripe water"): traditional and Ayurvedic medicines recommend "gripe water," an infusion of dill seed in water, as a sleep and digestive aid, especially for children.
- Topical oil: Used in clinical trials for dermatological endpoints (see Section 7).
2. Traditional and Historical Use
Ancient Civilizations
The earliest known record of dill as a medicinal herb was found in Egypt 5,000 years ago, when the plant was referred to as a "soothing medicine." Around 3,000 B.C.E., the Babylonians were known to have grown dill in their gardens.
Although several twigs of dill were found in the tomb of Amenhotep II, the earliest archaeological evidence for its cultivation comes from late Neolithic lake shore settlements in Switzerland.
Dill was popular in ancient Greek and Roman cultures, revered for its healing properties and considered a sign of wealth; it was used by Hippocrates. Traces have been found in Roman ruins in Great Britain. Charlemagne used it for his banquets so guests could benefit from its carminative properties.
Dill-scented oil was burned in Greek homes, and the plant's essential oil was used to make some of their wine. Dioscorides, a Greek doctor and surgeon, wrote that scorched dill seeds were used to aid with healing wounded soldiers, a practice also shared by the Romans.
In Semitic languages, dill is known by the name Shubit. The Talmud requires that tithes shall be paid on the seeds, leaves, and stem of dill.
Etymology
Dill's name comes from the Old Norse word dilla, which means "to lull" or "soothe," possibly referring to its antigas and digestive-aiding properties.
Medieval and Renaissance Europe
As Europe entered the Middle Ages, dill gained further prominence. Monastery gardens became its home, as the herb was cultivated for its culinary and medicinal attributes. In traditional folk medicine, dill was utilized to aid digestion and treat various ailments, including colic and insomnia.
Regional and Ethnopharmacological Traditions
Seeds are described in traditional South Asian sources as stomachic, antipyretic, carminative, antidysenteric, diuretic, laxative, anthelmintic, and used to treat gastric ulcers, abdominal pain, eye diseases, and urinary pains. It is also used for treatment of griping pains. Dried and ripe fruits are used in pediatric complaints, such as flatulence and weak digestion.
Dill is also used for liver problems, and heart and circulatory system diseases in Pakistan. It has local medicinal uses in Iraq (Kurdistan) for various diseases such as stomach, kidney, and liver problems, and for back and arthritis pain and blood cholesterol.
Dill has been extensively used as a traditional herbal medicine throughout Central America for carminative, diuretic, soporific, and galactagogue therapeutic purposes.
In herbal medicine traditions, dill has been used for the treatment of mental disorders, convulsions, asthma, thyroid diseases, to regulate the menstrual cycle, to reduce labour pain, to increase milk production in lactating women, to prevent colic in babies, and to alleviate pain.
In Persian medicine, Anethum graveolens has been traditionally used as a skin softener and purifying agent.
3. Phytochemistry: Key Constituents and Active Compounds
Essential Oil: Volatile Fraction
The major components of Anethum graveolens L. essential oils (yielding 1–4%) are α-phellandrene, limonene, carvone, furanocoumarin, dill ether, dillapiole, and geraniol, but their content differs in the seed (fruit) versus the vegetative herb.
There is some diversity in dill composition in different countries; for example, American dill oil has a high amount of alpha-phellandrene, while carvone and limonene are the main constituents of Asian and European dill.
The terpenic fraction of essential oil from non-shaded plants consists mainly of oxygen-containing monoterpene derivatives (53.6%), with carvone (46.1%) as the primary component, followed by monoterpene hydrocarbons (46.4%), predominantly limonene (43.8%). Essential oil from shaded plants contains a higher content of carvone (49.8%) and a lower content of limonene (37.8%).
Carvone is the predominant odorant of dill seed; α-phellandrene, limonene, dill ether, and myristicin are the most important odorants of dill herb.
The phenylpropene volatiles dillapiole and apiole impart one of the characteristic aromas of dill weeds.
Other volatile constituents include pinene, diterpene, dihydrocarvone, cineole, myrcene, paramyrcene, isomyristicin, myristicin, myristin, apiol, and dillapiol. A. graveolens essential oil also contains furanocoumarin, oxypeucedanin, oxypeucedanin hydrate, and falcarindiol.
The oil content in the dill herb ranges from 0.10% to 0.30% (v/fresh weight), and in the dill seed from 1.75% to 4.0% (v/dry weight).
Non-Volatile Fraction: Phenolics, Flavonoids, and Other Compounds
Dill contains several phenolic acids such as vanillic, caffeic, ferulic, chlorogenic, and rosmarinic acids. It also includes flavonoids like gallic acid, quercetin, and kaempferol that contribute to its bioactive properties.
Chemical analysis of plant parts has established the presence of flavonoids (rutin, quercetin), hydroxycinnamic acid derivatives (caffeic acid, chlorogenic acid), coumarins (scopoletin), sterols (beta-sitosterol/stigmasterol), and mucilages.
Two flavonoids have been isolated from A. graveolens seeds: quercetin 3-O-beta-D-glucuronide and isorhamnetin 3-O-beta-D-glucuronide, which have antioxidant activities and could counteract free radicals.
Gas chromatographic analysis of the crude aqueous extract has identified 29 known flavonoids (mainly 47.71% kaempferol and 37.36% quercetin), four saponins, six hydroxycinnamic acid derivatives (mainly p-coumaric and caffeic acid), ten carotenoids, and seven phytosterols (mainly 98.16% sitosterol).
Macro- and Micronutrients
Dill leaves are a rich source of minerals, proteins, and fiber, containing 36% carbohydrates, 15.68% protein, 14.80% fiber, and 8.39% moisture, in addition to essential oils, fatty acids, and vitamins.
In addition to essential oils, dill contains fatty oil, proteins, carbohydrates, moisture, fiber, ash, vitamins (A and niacin), and mineral elements (calcium, potassium, magnesium, phosphorus, and sodium).
4. Mechanisms of Action
Carminative and Antispasmodic Activity
Dill is a carminative digestive herb. Its volatile oils relax smooth muscle in the gastrointestinal tract, reducing spasms while supporting digestive secretions. Carvone is believed to be responsible for its carminative (gas-relieving) properties.
Hypolipidemic Mechanisms
Several primary mechanisms have been proposed for hypolipidemic effects. Inhibition of intestinal cholesterol absorption, binding to bile acids in the intestine, an increase in fecal excretion, and increasing production of bile acids may be the main mechanisms by which dill exerts its antidiabetic functions.
Some components of A. graveolens such as carvone, limonene, or α-phellandrene are responsible for the hypolipidemic properties, likely through reducing acyl-CoA carboxylase or 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, the key enzymes in fatty acid and cholesterol metabolism.
The mechanism may also relate to the decreased absorption of cholesterol by binding to bile acids, the inhibition of cholesterol and fatty acid synthesis through suppression of acetyl-CoA carboxylase and HMG-CoA reductase activity, and the stimulation of cholesterol clearance by increasing LDL receptors.
Antioxidant Activity
Different concentrations of dill extract (0.125, 0.25, 0.5, and 1 mg/mL) have shown potential antiradical and antioxidant activity. Aqueous extract of dill significantly reduced advanced glycation end-product (AGE) formation and fructosamine levels, protein carbonyl oxidation, amyloid cross-β structure, and protein fragmentation.
For anti-inflammatory activity, inhibition of nitric oxide (NO) molecules and interleukins 1 and 6 in macrophages (RAW264.7 cell line) was detected, alongside gene expression of inducible nitric oxide synthase (iNOS). The strength of antioxidant activity was ranked: vitamin C > ethyl acetate fraction > n-butanol fraction > water fraction > ether fraction.
Antimicrobial Mechanisms
The essential oil of dill exhibits various biological activities such as antimicrobial, antifungal, antioxidant, insecticidal, anti-inflammatory, antispasmodic, antidiabetic, anticancer, and anti-hypercholesterolemia effects, due to the presence of biologically active compounds.
D-limonene and D-carvone have exhibited strong antifungal activity against Aspergillus niger, Saccharomyces cerevisiae, and Candida albicans.
Antiglycation and Antidiabetic Mechanisms
A. graveolens acts mainly by affecting antioxidant capacity and inducing change in some genes in glucose and lipid pathways.
Drug-Metabolizing Enzyme Induction
In cell studies, dill extract up-regulated certain drug-metabolizing enzymes (like CYP1A2, CYP2C19, SULT1A1, NAT2) and a transporter protein (ABCB1), suggesting that long-term or high-dose dill use might influence the metabolism of some drugs, although human clinical evidence is lacking and this remains theoretical.
5. Scientific Evidence by Area of Use
5.1 Glycemic Control and Diabetes Management
There is evidence that Anethum graveolens has been used for centuries in Asian traditional medicine, and its constituents have useful effects on the control and management of diabetes and cardiovascular disorders. It has many useful effects, including hypolipidemic and hypoglycemic effects, and has been reported to reduce the incidence of diabetic complications.
Key clinical study (RCT, 2020): The objective of this study was to investigate the effects of Anethum graveolens powder supplementation on glycemic control, lipid profile, antioxidant and inflammatory markers, and gastrointestinal symptoms in patients with type 2 diabetes. Forty-two patients with type 2 diabetes were randomly allocated to intervention and control groups and received either 3 g/day dill powder or placebo (3 capsules/day, 1 g each). Fasting blood sugar, insulin, HOMA-IR, lipid profile, high-sensitivity C-reactive protein, total antioxidant capacity, and malondialdehyde were measured at baseline and post-intervention.
The dill powder supplementation significantly decreased the mean serum levels of insulin, homeostatic model assessment of insulin resistance (HOMA-IR), LDL-cholesterol, total cholesterol, and malondialdehyde in the intervention group compared with baseline. Patients who received 3 g/day A. graveolens had lower levels of MDA (malondialdehyde) and higher levels of total antioxidant capacity (TAC) than patients in the control group. MDA is a product of lipid peroxidation and is recognized as an atherogenic agent.
Systematic review and meta-analysis (2022): Dose-response analysis showed a significant reduction in fasting blood sugar at doses of 1,500 mg/d. The meta-analysis indicated that Anethum graveolens could exert favorable effects on insulin resistance and serum LDL.
In diabetic models, the administration of different extractions of A. graveolens seed had antioxidant, hypolipidemic, and hypoglycemic effects. Earlier studies reported inconsistent findings regarding the protective effects of A. graveolens.
Animal/in vitro evidence: After 2 months of treatment, blood glucose levels (P=0.006) and AGE formation (P=0.003) were significantly reduced in a dill-treated group compared with untreated diabetic animals.
Evidence strength: Preliminary to moderate. Multiple small-to-moderate RCTs and a meta-analysis support modest glycemic and insulin-resistance benefits. Early human trials suggest modest improvements in glycemic and lipid markers with standardized dill fruit powder/extracts, but larger, well-controlled studies are required before strong therapeutic claims.
5.2 Lipid Profile and Cardiovascular Risk Factors
Systematic review and meta-analysis (2021, PubMed PMID 34838903): Pooled data from 6 RCTs involving 171 intervention cases indicated that dill supplementation was associated with a significant reduction in mean serum total cholesterol (MD = −3.71; P < 0.001), LDL-cholesterol (MD = −1.51; P = 0.005), triglycerides (MD = −2.48; P = 0.001), and HDL-cholesterol (MD = −2.19; P = 0.002).
Subgroup analysis showed that dill use was more effective in lowering triglycerides in both hyperlipidemic patients and type 2 diabetics. Dill use reduced LDL levels more effectively in patients with type 2 diabetes.
Individual RCT comparing dill to gemfibrozil (2014, PMC4235097): In this clinical study, 91 hyperlipidemic patients were randomly designated into two groups. One group received gemfibrozil (900 mg daily) and the other group received dill tablet (six tablets daily) for 2 months. Blood lipids were assessed at the beginning and end of the trial. Use of gemfibrozil produced increased HDL-cholesterol by 3.91% and reduced triglyceride and total cholesterol by 32.7% and 9.41%, respectively. Applying dill tablet for 2 months resulted in reduction of total cholesterol up to 18% (P < 0.05) and triglyceride by 7.38% (P < 0.05).
Dill supplementation significantly improved LDL-C, TG, and total cholesterol levels but not HDL-C. Further high-quality controlled clinical trials are needed.
Given the inconclusive results related to glycemic, lipid, and inflammatory profiles, it is not clear whether dill can be helpful. The role of dill and its compounds on the improvement of cardiovascular risk factors is conflicting.
Evidence strength: Preliminary to moderate. Meta-analytic pooling yields statistically significant improvements in total cholesterol, LDL, and triglycerides, but the constituent studies are small and heterogeneous. An RCT in metabolic-syndrome patients at 12 weeks showed improvements in lipid profile at some endpoints; results were heterogeneous. Systematic overviews stress the need for larger, well-controlled RCTs before firm conclusions.
5.3 Gastrointestinal Health: Carminative, Antispasmodic, and Gastroprotective Effects
In traditional herbal medicine, A. graveolens is used to treat gastrointestinal ailments such as indigestion and flatulence.
Preclinical evidence: A. graveolens seed extracts possess significant mucosal protective and antisecretory effects in gastric mucosa lesions induced in mice by oral administration of HCl (1N) and absolute ethanol. The acidity and total acid content were reduced by orally or intraperitoneally administered extracts. Anethum graveolens seed extracts exerted moderate activity against Helicobacter pylori.
GI smooth-muscle antispasmodic/carminative activity has been observed in preclinical models, forming the basis for traditional dyspepsia/colic uses.
Evidence strength: Traditional use supported by preclinical (animal and cell) data. Contemporary human studies are sparse. The clinical translation of these findings to humans has not been adequately established in robust RCTs.
5.4 Antimicrobial and Antifungal Activity
The antibacterial activity of dill essential oil has been tested on three Gram-positive bacteria (Bacillus cereus, Staphylococcus aureus, and Streptococcus faecium) and three Gram-negative bacteria (E. coli, Salmonella typhi, and Shigella dysenteriae) using the disk diffusion agar method.
The results of the disk diffusion method show that Anethum graveolens essential oil exhibits strong antibacterial activity against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, and moderate antifungal activity against Fusarium graminum and Alternaria alternata. The pure essential oil showed a moderate antioxidant activity with inhibition percentages of 49.93 ± 4.58%.
Studies have shown that dill has antibacterial and antifungal activity, particularly against Candida species.
Evidence strength: Primarily in vitro. Human clinical data on antimicrobial endpoints are absent. These findings establish a biological basis for traditional antimicrobial uses but do not constitute clinical evidence of efficacy in human infections.
5.5 Antioxidant and Anti-inflammatory Activity
Dill is a functional herb known for its dietary, medicinal, and health-promoting agents, enriching antioxidants that help to protect cells from oxidative stress and may reduce the risk of several chronic diseases.
Phytochemicals like limonene, rutin, caffeic acid, kaempferol, isoquercitrin, alpha-tocopherol, hyperoside, and alpha-terpineol have shown considerable antineoplastic effects in numerous studies; ferulic acid and chlorogenic acid have proved to possess protective effects against many hepatic tumors.
Evidence strength: Primarily in vitro and animal studies. The anti-inflammatory and antioxidant properties of dill are well characterized at the cellular level; clinical trials directly targeting these endpoints as primary outcomes are limited.
5.6 Topical Application: Uremic Pruritus
One clinical trial examined the efficacy of topical application of Anethum graveolens oil on pruritus severity, skin dryness, sleep quality, and quality of life in patients undergoing hemodialysis. Participants were randomly assigned to one of three groups: topical dill preparation, sesame oil, or a control group receiving no treatment. The study was double-blind and placebo-controlled. The topical treatment was applied twice a day for one month to areas of skin affected by pruritus. Outcome measures included the severity of skin dryness, Pittsburgh Sleep Quality Index, Duo's Uremic Pruritus Severity Scale, and the Itchy QoL questionnaire.
Evidence strength: A single pilot RCT; findings are preliminary and require replication in larger studies.
5.7 Neurological: Anticonvulsant Effects
Dill leaves have been used as a folk medicine to treat seizure in Iran, and the presence of flavonoids in this plant is notable. The anxiolytic characteristics of flavonoids have been rarely examined, and the anxiolytic-like effects of simple flavones like chrysin have been reported. This flavone behaves as a competitive ligand of benzodiazepine receptors and has been shown to prevent the expression of tonic-clonic seizures induced by pentylenetetrazol in mice.
Evidence strength: Animal model data only. No human clinical trials have investigated dill's anticonvulsant properties.
5.8 Reproductive and Gynecological Uses
Dill is traditionally used as an antispasmodic for painful menstruation and as an emmenagogue to help regulate the menstrual cycle. Some practitioners also use it to support lactation. In formulas, it is often paired with fennel, aniseed, or fenugreek to enhance galactagogue effects, though human clinical evidence is limited.
Evidence strength: Traditional use only; human clinical evidence is sparse and not conclusive.
6. Body Systems and Health Areas Associated with Dill
- Gastrointestinal system: Traditional herbal medicine uses dill for digestive diseases, stomach pain, and breathing problems. Carminative and antispasmodic use is the best-established traditional application.
- Cardiovascular/metabolic system: Numerous studies have demonstrated pharmacological effects of dill as a hypolipidemic, antidiabetic, and anti-inflammatory agent.
- Immune and antimicrobial defense: A. graveolens has been shown to have anticancer, antimicrobial, anti-gastric irritation, anti-inflammatory, and antioxidant properties.
- Urinary system: Dill has mild diuretic properties, which can be supportive in urinary tract infections and for gently flushing the urinary system. Ayurvedic practitioners use dill as a mild diuretic.
- Nervous system: Preclinical evidence for anticonvulsant and sedative effects exists, attributed to flavonoid content.
- Skin: Traditionally used as a skin softener; one RCT investigated topical dill oil for uremic pruritus.
- Reproductive system: Galactagogue and emmenagogue traditional uses are documented across multiple cultures; clinical evidence is limited.
7. Dosages Reported in Clinical and Scientific Studies
In one RCT, 42 patients with type 2 diabetes received either 3 g/day dill powder or placebo (3 capsules/day, 1 g each).
In a clinical study comparing dill to gemfibrozil in 91 hyperlipidemic patients, one group received dill tablet at six tablets daily for 2 months.
Dose-response analysis in a meta-analysis showed a significant reduction in fasting blood sugar at doses of 1,500 mg/day.
In a trial examining topical dill oil for uremic pruritus, the topical treatment was applied twice a day for one month to affected areas of the skin.
No universal standardized therapeutic dosage has been established in authoritative pharmacopeial monographs for dill as a supplement. Dosages used across reviewed clinical studies range from approximately 1,500 mg to 3,000 mg per day of powdered seed/fruit for oral supplementation.
8. Safety, Adverse Effects, and Drug Interactions
General Safety
Dill is generally considered very safe when used at culinary and therapeutic doses. Rare allergic reactions can occur, particularly in individuals sensitive to plants in the Apiaceae family.
Allergic Reactions and Sensitization
Although rare, dill can trigger allergic reactions, especially in people allergic to celery, carrots, or fennel. Cross-reactivity with carrot, celery, and fennel allergies has been documented in clinical studies.
An inflammatory skin reaction following contact with light-sensitizing compounds in dill and long-wave ultraviolet light has been documented. Hives from contact with dill have been reported.
A case report describes a woman who reported allergic reactions to Indian dill (and cashew apple) who had a severe allergic reaction to mango.
Carvone and limonene oxidation products may sensitize skin; use of fresh, well-stored oils and proper dilution is advisable.
Gastrointestinal Adverse Effects
GI upset is possible with large doses of extracts or oils.
Pregnancy and Lactation
Traditionally, dill has been used as a contraceptive and to induce labor. Extracts of the seeds may have teratogenic effects. It is therefore not recommended during pregnancy.
Dill has traditionally been used to support lactation and ease infant colic, so it is generally considered safe in lactation.
Drug Interactions
The TRC Database specifically lists moderate interactions with lithium and antidiabetic drugs based on theoretical pharmacologic effects. Dill may act like a mild diuretic, which could alter how the body excretes lithium. This can potentially increase lithium levels in the body.
The potential for additive glucose-lowering with dill supplements used for glycemic endpoints is noted; monitoring of glucose and adjustment of therapy may be needed when combining with antidiabetic drugs.
However, the interaction with antidiabetic drugs is a theoretical risk and there are no studies or cases that confirm this interaction.
Patients with pollen-related (e.g., mugwort/birch) spice allergy may react to dill; coordination with an allergist is warranted.
Regulatory Status
Scientific research on the uses of dill is limited. In preliminary research, dill has demonstrated dose-dependent cholesterol-lowering effects. At this time, clinical evidence supporting the efficacy of dill for any indication is limited.
References
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