Holy basil (tulsi)

Why people use it

Holy basil, or tulsi, is a sacred Ayurvedic herb also cooked across Southeast Asia. Small human studies have explored stress, blood sugar and immune measures, and a recent extract trial reported lower perceived stress, but the World Health Organization lists no use supported by clinical data and the pregnancy caution rests on animal studies.

• ✓Ayurvedic and Siddha traditional herb for stress and resilience
• ✓Daily tea and courtyard devotional plant in India
• ✓Thai and Southeast Asian cooking (kaphrao)
• ✓Small trials on stress, glucose and immune markers

What the evidence says

A 2017 systematic review found 24 small human studies on metabolic, stress and immune outcomes, all reporting favorable results with no significant adverse events, but the studies were heterogeneous in preparation and often unblinded. The WHO monograph states that no use is supported by clinical data. A 2022 industry-funded randomized trial of one standardized extract reported lower perceived stress and smaller blood-pressure rises under acute stress, and a 1996 crossover trial of leaves showed a modest fall in fasting glucose.

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Common forms

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Tea, powder, standardized extract and essential oil are different exposures. Study findings apply only to the preparation tested, and essential oil safety is unrelated to leaf safety.

Traditional and practitioner context

Ocimum tenuiflorum is traditionally used in Ayurveda and Siddha medicine, where it is often called the elixir of life, in preparations for fever, cough, cold and digestive complaints, and the WHO monograph records a traditional decoction of crude leaf. In Hindu households tulsi is cultivated in the courtyard and used in daily worship, a practice widely documented in ethnobotanical literature. In Thailand the same species, kaphrao, is the herb of pad kaphrao stir-fries, and it is known as kemangi or selaseh in Indonesia and Malaysia.

Foraging index

Garden and container plant in North America

USDA PLANTS records holy basil as introduced only in Puerto Rico and the Pacific Basin, with no wild record in the continental United States; it is a garden and container plant here. Do not confuse it with sweet basil or Thai basil (Ocimum basilicum), whose oils are methyl chavicol and linalool types, or with African clove basil (Ocimum gratissimum), which is sometimes sold as tulsi.

Status: cultivation only. Broad occurrence never confirms identity, safe use, legal access or permission to harvest.