Dehi (Citrus aurantifolia): Lime, the Sour Fruit in Every Sri Lankan Remedy

Dehi (Citrus aurantifolia) is squeezed into more Sri Lankan remedies than any other plant: into the hot coriander tea for a cold, the salt-and-lime drink for a fever, the sambola that "cuts" a heavy meal, the paste rubbed on a scalp for dandruff. It is also the fruit that protected sailors from scurvy and gave the British Navy the nickname "limeys". Recent research has found something the old remedies never anticipated — the peel may help you sleep.

Botanical and Cultural Background

The lime is a small, thorny evergreen citrus, probably native to Southeast Asia, grown across Sri Lanka's low country in home gardens and small orchards. The small, thin-skinned, intensely aromatic fruits are picked green. Every part is used: the juice (rich in citric acid and vitamin C), the peel (essential oils and flavonoids such as hesperidin and naringin), and the leaves (in fever decoctions). In folk belief a lime cut in the home wards off ill fortune — a small sign of how central the fruit is to daily life.

Traditional Uses in Sri Lankan Medicine

• Colds, coughs and fevers — lime juice in hot coriander tea with bee honey; the salt-lime drink for fevers and heat exhaustion.
• Digestion — a squeeze of lime after rich food; lime pickle as an appetite stimulant.
• Skin and scalp — juice for dandruff, acne and insect bites; peel rubbed on rough skin.
• Nausea and vomiting — lime juice with a pinch of salt and sugar, a folk oral rehydration drink.

What the Research Shows

A 2025 comprehensive review in Food Bioscience mapped the fruit's bioactive compounds and confirmed antioxidant, antimicrobial, anti-inflammatory and cardiovascular effects in laboratory and animal studies, with the flavonoids in the peel drawing particular interest. The surprise came in 2024: a standardised lime-peel extract was shown to enhance non-REM sleep in animal studies by activating GABA-A receptors, the same target as prescription sleep medicines, and a 2025 regulatory toxicology study found the extract safe in acute, 90-day and genotoxicity testing. The traditional uses rest on solid ground — vitamin C and antimicrobial oils explain the cold remedies, and the salt-lime drink is a reasonable oral rehydration fluid — but human trials of lime as a medicine remain few.

Evidence updated September 2026.

How Dehi Is Prepared

For a cold, squeeze half a lime into a cup of hot koththamalli tea and add a spoon of bee honey once it has cooled slightly (heat destroys some vitamin C). The fever drink is the juice of one lime in a glass of water with a pinch of salt and a teaspoon of sugar. For dandruff, massage fresh juice into the scalp, leave twenty minutes and rinse. Lime pickle uses whole limes salted and sun-cured for weeks.

Safety and Precautions

Lime is safe as a food for all ages. Its acid erodes tooth enamel with frequent sipping — rinse afterwards — and can aggravate reflux and gastritis. Lime peel oil on the skin causes phytophotodermatitis: painful burns and dark marks when skin exposed to the juice or peel is then exposed to sun. Wash hands and skin after handling limes outdoors, and never apply lime to skin before sun exposure.