Shiso / Perilla (Perilla frutescens): Culinary Uses, Traditional Medicine, Research & Safety

Shiso is the Japanese culinary name most strongly associated with Perilla frutescens var. crispa, an aromatic annual herb in the mint family. The wider species, Perilla frutescens, is grown throughout East and Southeast Asia for leaves, seeds, seed oil, medicine, seasoning and food preservation.

Red shiso, green shiso, Korean perilla leaves and oilseed perilla are closely related, but they are not always identical cultivars or varieties. This matters because leaf flavor, volatile chemistry, anthocyanin content, seed production and traditional use can differ. It also matters when reading research: a study on perilla seed oil is not automatically evidence for a cup of shiso-leaf tea, and an essential-oil study is not the same as eating fresh leaves with dinner.

Botanical Identity

Accepted species: Perilla frutescens (L.) Britton
Family: Lamiaceae
Genus: Perilla
Shiso variety: Perilla frutescens var. crispa (Thunb.) H.Deane
Oilseed/broader cultivated variety: Perilla frutescens var. frutescens

Royal Botanic Gardens, Kew currently recognizes only one accepted species in the genus Perilla: P. frutescens. It recognizes several varieties within that species, including var. crispa and var. frutescens. Kew’s economic-botany records specifically associate the Japanese common name shiso with var. crispa.

Common Names

Depending on region, cultivar and plant part, common names include:

  • shiso;
  • red shiso / purple shiso;
  • green shiso / aojiso;
  • perilla;
  • beefsteak plant;
  • purple mint;
  • Korean perilla or Korean sesame leaf;
  • Zi Su / Zi Su Ye in Chinese herbal contexts for the leaf;
  • Zi Su Zi for the fruit/seed in Chinese materia medica.

Because common names overlap, the botanical name and plant part should be stated on medicinal or research-oriented products.

Identification

Perilla is an aromatic annual with square stems, opposite toothed leaves and flower spikes typical of many members of the mint family. Leaves may be green, purple-red, two-toned, flat or strongly ruffled depending on variety and cultivar.

The aroma is distinctive and difficult to describe with one comparison: people variously detect mint, basil, cinnamon, anise, clove, citrus and cumin-like notes. Much of that character comes from volatile compounds such as perillaldehyde and other terpenoids.

Green Shiso vs. Red Shiso

Green shiso is widely used fresh as a garnish, wrap or aromatic vegetable. It is common with sushi, sashimi, noodles, rice, salads, tempura and pickled foods.

Red or purple shiso contains substantial anthocyanin pigments and is famous for coloring and flavoring umeboshi and other pickles. The pigment profile is one reason red-leaved forms receive separate research interest.

Both belong within the same broader species complex, but their chemistry is not identical enough to assume that every study applies equally to every red and green cultivar.

Korean Perilla Leaves

Korean perilla leaves are commonly eaten as leafy vegetables and wraps and are used in pickles, soups, stews and seasoned side dishes. They are often somewhat broader and differently flavored from Japanese shiso cultivars.

The English word “perilla” may therefore refer to several culinary forms, while “shiso” usually points more specifically toward Japanese var. crispa traditions.

Traditional Chinese Herbal Parts

Chinese medicine distinguishes different parts of perilla rather than treating the entire plant as one interchangeable drug.

  • Zi Su Ye — perilla leaf, traditionally used in aromatic formulas involving the exterior, cough, chest or digestive discomfort.
  • Zi Su Zi — the ripe fruit/seed, traditionally used differently, especially in cough, phlegm and bowel traditions.
  • Zi Su Geng — the stem, used in still another set of traditional indications.

That distinction is important. A paper studying seed oil cannot simply be filed as proof for a leaf preparation, and a leaf-extract study cannot establish the medicinal action of the seeds.

Major Constituents of the Leaves

Reviews identify hundreds of compounds across the plant. Particularly important groups include:

  • rosmarinic acid and other phenolic acids;
  • perillaldehyde and other volatile terpenoids;
  • luteolin, apigenin and related flavonoids;
  • anthocyanins in red-purple forms, including shisonin-related pigments;
  • triterpenes, carotenoids and phytosterols;
  • polysaccharides under active modern investigation.

The volatile profile varies substantially by chemotype, cultivar, climate and growing conditions. This is why the smell of two plants sold as “perilla” can differ dramatically.

Human Research: Seasonal Allergies

One of the better-known human studies used an oral Perilla frutescens extract enriched in rosmarinic acid in people with mild seasonal allergic rhinoconjunctivitis. The trial was randomized, double-blind and placebo controlled, but small: 29 participants received either 50 mg, 200 mg or placebo for 21 days.

The active groups showed improved responder rates for several nasal and eye symptoms, along with reductions in inflammatory cells in nasal-lavage fluid. No significant laboratory abnormalities or adverse events were reported in that short study.

This is useful evidence for a specific rosmarinic-acid-enriched extract. It does not establish that ordinary shiso leaves are a proven substitute for antihistamines, inhalers or medical treatment of severe allergy.

Anti-Allergic and Anti-Inflammatory Research

Perilla has a substantial preclinical literature involving mast cells, inflammatory mediators, leukotrienes, cytokines, oxidative pathways and allergic responses. Rosmarinic acid, luteolin and related compounds are frequently discussed as contributors.

The laboratory evidence helps explain the long-standing interest in perilla for allergy and inflammatory conditions, but clinical research remains far smaller than the preclinical literature. Broad claims that shiso “treats asthma” or “stops allergies” go beyond the evidence.

Perilla Seed Oil

Perilla seed oil is nutritionally different from the leaf. The seeds can contain roughly 35–45% oil, and reviews consistently describe the oil as unusually rich in the plant omega-3 fatty acid alpha-linolenic acid (ALA). Reported ALA proportions are often around 50–65% of total fatty acids, though actual composition varies.

This makes perilla oil interesting as a culinary omega-3 source, particularly in Asian diets. It is not identical to marine EPA/DHA oils: the human body can convert some ALA into longer-chain omega-3 fatty acids, but conversion is limited.

Oxidation and Storage of Perilla Oil

The same high polyunsaturated-fat content that makes perilla oil nutritionally interesting also makes it relatively vulnerable to oxidation. Light, heat and oxygen accelerate rancidity.

Fresh culinary oil should be stored according to manufacturer directions, typically tightly closed and protected from heat and light. Strong rancid odors or flavors indicate deterioration rather than extra medicinal strength.

Digestive and Respiratory Traditions

Traditional East Asian medicine uses perilla leaf, stem and seed in different ways for nausea, abdominal discomfort, cough, phlegm and other pattern-based complaints. Modern reviews document antispasmodic, anti-inflammatory and respiratory-related effects in experimental studies.

Human clinical evidence remains too limited to describe perilla as a proven treatment for asthma, chronic cough, reflux or gastrointestinal disease. Its culinary and traditional digestive roles are better established than disease-specific clinical claims.

Mood and Nervous-System Research

Animal and laboratory studies have explored antidepressant, anxiolytic and neuroprotective effects of perilla extracts and constituents. These studies are interesting but remain primarily preclinical. Shiso should not be presented as an established antidepressant or treatment for neurological disease on that basis.

Perilla Ketone and Livestock Toxicity

One of the most confusing safety topics around perilla is perilla-ketone poisoning in grazing livestock. Certain forms of Perilla frutescens, especially at flowering or seed stage, can contain perilla ketone and related compounds that cause severe pulmonary edema and respiratory distress in susceptible cattle and other grazing animals.

Experimental cattle research found the flowering/seed-stage material to be particularly toxic. This veterinary toxicity is real and important for pasture management.

It should not be distorted into the statement that Japanese shiso leaves are a poisonous human food. Shiso and other edible perilla forms have extensive culinary histories. Species variety, chemotype, plant stage, quantity, route of exposure and animal susceptibility all matter.

Human Safety

Ordinary culinary leaf use has a long food history. Concentrated extracts and volatile-oil preparations require a different level of caution because their exposures are much greater and may represent different chemotypes.

  • Allergy: as with any food or herb, perilla itself can cause allergic reactions in susceptible people.
  • Pregnancy and breastfeeding: culinary food amounts are different from medicinal extracts. High-quality human safety data for concentrated medicinal preparations are limited.
  • Medication interactions: formal human interaction studies are sparse. Concentrated extracts should not automatically be assumed neutral with anticoagulant, antiplatelet, anti-inflammatory or other prescription medicines.
  • Essential oil: volatile perilla oil is not interchangeable with edible seed oil. Essential-oil exposure is far more concentrated and requires appropriate formulation and safety assessment.

Growing Shiso

Shiso is an annual and is commonly grown from seed. It prefers warmth, adequate moisture and sun to partial sun. Germination can be slower or more erratic than many common culinary herbs, and fresh seed often performs better than old seed.

Pinching young plants encourages branching. Leaves can be harvested repeatedly before flowering. Once established, perilla may self-seed enthusiastically, and in parts of North America escaped populations of P. frutescens have naturalized.

Harvesting and Preserving Leaves

Fresh leaves are best harvested before they become weathered or overly tough. Use clean, undamaged leaves and wash them as you would other leafy vegetables.

Leaves can be used fresh, salted, pickled, dried or frozen depending on the culinary tradition. Drying changes the volatile aroma, so dried shiso does not taste exactly like fresh leaf.

Sourcing and Identification

If you specifically want Japanese shiso, look for Perilla frutescens var. crispa or a named shiso cultivar rather than assuming every seed packet labeled “perilla” will produce the same leaf.

For seed oil, look for food-grade perilla seed oil with clear storage instructions and a recent production date. For herbal products, the label should state the plant part because leaf, stem and seed have different traditional uses and chemical profiles.

Bottom Line

Shiso is best understood as a culinary and medicinally interesting form of the broader species Perilla frutescens, especially var. crispa. The leaves provide aromatic terpenes, rosmarinic acid, flavonoids and, in purple forms, anthocyanins. The seeds are a completely different nutritional material and produce an oil unusually rich in ALA omega-3 fatty acid.

Human research is still modest, although a small placebo-controlled trial of a rosmarinic-acid-enriched perilla extract found improvement in seasonal allergy symptoms. Much of the broader pharmacology remains preclinical. The plant’s well-documented livestock toxicity at certain stages should be respected in animal husbandry without being sensationalized into a claim that normal culinary shiso is poisonous to humans.

This article is for botanical and educational purposes only and is not medical advice. Culinary food use, traditional medicinal preparations, standardized extracts, seed oil and essential oil are different exposures and should not be treated as interchangeable.

Research & Reference Sources

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