Lamiaceae
Ocimum tenuiflorum
Tulsi · Holy basil
- Part used
- leafaerial
- Native range
- Indian subcontinent and Southeast Asia
- Morphology
- An aromatic subshrub to about a metre, often with purple-tinged toothed leaves and whorls of small purple flowers on slender spikes. Strongly clove-scented.
- Also known as
- Ocimum sanctum
What is in it
Evidence
Small trials report effects on stress, blood glucose and lipids. Reviews consistently note that the studies are small, short and mostly conducted in one region.
Safety
Generally well tolerated as a tea. Antifertility effects are reported in animal studies and it is traditionally avoided when trying to conceive. Methyl eugenol is a recognised genotoxic carcinogen in animal studies, which matters for concentrated preparations rather than for tea. Antiplatelet activity reported.
Interactions: Additive with anticoagulants; May lower blood glucose
Regulatory: Permitted as a food and as a listed medicine ingredient.
How the traditions classify it
Three systems, rating the same plant. Where they disagree, none of them is correcting the others — they are separate frameworks that arrived at their categories independently.
Historical use
Sacred to Vishnu and grown in courtyards across Hindu households, where it is venerated rather than merely cultivated. Its medicinal and its religious roles are not separable in practice.
Recorded as history and attributed where possible. Long use establishes that a plant was widely used, not that it worked, and not that it was safe.
Worth knowing
Tulsi is the entry in this collection where the line between a medicinal plant and a religious object is least meaningful. It is grown in a dedicated raised planter in Hindu households, watered as an observance, and treated as a manifestation of a goddess. It is also drunk as a tea for coughs.
Describing it purely as a medicinal herb, which every supplement listing does, removes most of what it is. That is worth noticing about the whole enterprise of extracting a materia medica from a living tradition: the plants arrive in the West stripped of everything except their claimed effects, which is precisely the part that tends not to survive testing.
Nomenclature verified against GBIF backbone taxonomy.