Kohila (Lasia spinosa): The Spiny Marsh Vegetable That Fights Inflammation

Kohila (Lasia spinosa) is the vegetable that bites back: a marsh plant whose leaf stalks and rhizomes are covered in short thorns that must be scraped off before the pale, crunchy flesh can be sliced into one of Sri Lanka's most distinctive curries. Village physicians have long prescribed it for aching joints and piles, and it turns out to be one of the more promising anti-inflammatory plants to have been examined in the laboratory this decade.

Botanical and Cultural Background

A member of the arum family, kohila grows in swamps, paddy margins and stream banks throughout the low country, sending up deeply lobed leaves on spiny stalks from a thick creeping rhizome. Both the rhizome (kohila ala) and the young leaf stalks (kohila dalu) are eaten, usually as a dry curry with coconut, or as a mellum. The plant is also traditional food for new mothers and is believed to strengthen the body after illness.

Traditional Uses in Sri Lankan Medicine

• Piles (haemorrhoids) — the rhizome curry eaten regularly; the classic Sri Lankan food remedy for the condition.
• Joint pain and rheumatism — rhizome decoction, and the vegetable in the diet.
• Digestion and worms — leaf mellum as a mild digestive; rhizome juice for intestinal worms.
• Coughs — leaf decoction in some regional traditions.

What the Research Shows

A 2021 review in Oxidative Medicine and Cellular Longevity summarised the chemistry (flavonoids, phenolic acids, alkaloids) and reported consistent anti-inflammatory, analgesic, antioxidant and antimicrobial activity in laboratory and animal studies — a fair scientific basis for the joint-pain and piles traditions. In 2022 a team publishing in Pharmaceuticals showed that stem compounds lowered blood glucose and improved metabolic markers in diabetic animals, and in 2024 chemical profiling of the leaves and fruits found compounds with antioxidant and enzyme-inhibiting activity. As with most Sri Lankan vegetables, controlled human trials are still lacking; the evidence supports kohila as a genuinely functional food rather than a proven treatment.

Evidence updated September 2026.

How Kohila Is Prepared

Scrape the thorns from stalks and rhizome with a knife, wash well and slice thinly. For the classic curry, temper onion, curry leaves and a little chilli, add the kohila with turmeric and salt, and cook with a small amount of thick coconut milk until tender. Young leaves are shredded finely for mellum. For a medicinal decoction, a tablespoon of chopped dried rhizome is simmered in two cups of water until reduced by half.

Safety and Precautions

Kohila is a safe, nutritious vegetable when cooked; like other arum-family plants it contains calcium oxalate crystals, so it should never be eaten raw — cooking removes the irritation. Wash the plant thoroughly since it grows in muddy water. Concentrated rhizome preparations may add to the effect of glucose-lowering medicines. Harvest only from clean water; plants from polluted drains can accumulate contaminants.