How Ayurvedic herbs are used, what research suggests about 11 well-known ones, which medicines they can interact with, and how to buy and use them safely.
Medically reviewed by Dr. Nirmal P Raj & Dr. Chanthni Nirmal, BAMS, MD (Ayurveda) — Santhwana Siddha Clinic, Chalachal Siddha Varma Vidhyashala
Ayurvedic herbs are plants (and in some traditional preparations, minerals) used in Ayurveda as medicines, foods and tonics, usually prepared by a physician into a specific form and dose for the individual. Popular herbs such as ashwagandha, triphala, turmeric and tulsi are now sold worldwide as supplements, often with claims that run ahead of the evidence.
This guide explains how Ayurvedic herbs are classified and prepared, summarises what is traditionally claimed and what research suggests for eleven well-known herbs, and — most importantly — sets out the safety rules: interactions, who should avoid what, and how to avoid poor-quality products. It is general information, not medical advice.
In Ayurveda, medicinal plants and other substances are studied in a branch called Dravyaguna (the science of substances), which describes their taste, energetic qualities and effects on the doshas. A herb is rarely given alone for 'a symptom'; the physician chooses and combines substances to suit your dosha, digestion and condition, and decides the form, dose and what it is taken with (anupana) — for example warm water, milk or honey.
This is why advice such as "take X for Y" online is a poor guide. For the framework behind this, see our beginner's guide to Ayurveda and dosha guide.
External oils and internal medicines carry different risk profiles; our safety article explains why.
| Form | What it is | Typical use |
|---|---|---|
| Churna | Dry powder of one or more herbs | Mixed in warm water, honey or ghee (e.g. triphala churna) |
| Kashayam (kwatha) | Decoction boiled from herbs | Common in Kerala; taken in measured doses |
| Taila / Thailam | Medicated oil prepared by slow cooking herbs in oil | External massage (e.g. Abhyanga) or nasal/ear use; classical oils such as Kshirabala, Dhanwantharam and Mahanarayana are used for Vata conditions |
| Ghrita | Medicated ghee | Internal oleation in preparation for Panchakarma |
| Lehyam | Herbal jam or paste | Tonics taken in small spoonfuls |
| Gulika / vati / tablets | Compressed tablets | Convenient, standardised doses |
| Bhasma and rasa preparations | Specially processed mineral/metal preparations | Prescription-only, must be made to regulated standards — see the quality section below |
The table summarises traditional uses, what published research suggests, and the main cautions. 'Evidence' here means small clinical studies unless stated; none of this replaces a doctor's advice.
| Herb | Traditionally used for | What research suggests | Key cautions |
|---|---|---|---|
| Ashwagandha (Withania somnifera) | Stress, weakness, sleep, vitality | Several small trials suggest modest reductions in stress/anxiety scores and better sleep | Avoid in pregnancy; rare liver injury reports; may affect thyroid; sedative and immunosuppressant interactions |
| Triphala (amla + bibhitaki + haritaki) | Digestion, regularity | Small studies for constipation and digestive symptoms | Loose stools/cramps; avoid in pregnancy and diarrhoea; may add to blood-sugar-lowering effects |
| Brahmi (Bacopa monnieri) | Memory, calm, mental clarity | Some trials report modest memory benefits; results mixed | Nausea, cramps; take care with sedatives and thyroid or other regular medicines. Note 'brahmi' is also used for a different plant (Centella asiatica) in some regions |
| Turmeric / curcumin (Curcuma longa) | Inflammation, joints, skin, digestion | Some studies suggest modest benefit for osteoarthritis pain; absorption of plain turmeric is poor | Gallstones/bile-duct problems; may add to blood thinners; rare liver injury with concentrated supplements |
| Shatavari (Asparagus racemosus) | Women's health, lactation, vitality | Limited human evidence | Asparagus allergy; take advice in hormone-sensitive conditions; can act as a mild diuretic |
| Guggulu (Commiphora wightii) | Joints, weight, lipids | Cholesterol results mixed across trials | Avoid in pregnancy; thyroid caution; may interact with several medicines including some heart medicines |
| Tulsi (Ocimum sanctum) | Stress, cough and cold, general tonic | Small studies on stress and blood sugar | May lower blood sugar; avoid medicinal doses in pregnancy |
| Giloy (Tinospora cordifolia) | Fever, immunity | Limited good-quality trials | Liver injury has been reported, especially in people with autoimmune conditions; caution with diabetes medicines and in pregnancy |
| Amla (Phyllanthus emblica) | Digestion, rejuvenation, vitamin C | Small studies on lipids and blood sugar | May add to blood-sugar-lowering and mild blood-thinning effects |
| Neem (Azadirachta indica) | Skin conditions, oral care | Limited human evidence | Neem oil is toxic to infants; avoid in pregnancy and when trying to conceive; liver caution at high doses |
| Ginger (Zingiber officinale) | Nausea, digestion | Reasonable evidence for nausea relief | High doses may add to blood thinners; caution with gallstones |
| If you take… | Why take care | What to do |
|---|---|---|
| Blood thinners (e.g. warfarin) | Some herbs (turmeric, ginger, amla, garlic) may add to bleeding risk | Tell your doctor; do not start herbs without advice |
| Diabetes medicines or insulin | Tulsi, amla, triphala, guggulu and others may lower blood sugar further | Monitor sugar; take medical advice first |
| Thyroid medicines | Ashwagandha and guggulu may influence thyroid function | Check thyroid levels; do not self-treat |
| Blood-pressure and heart medicines | Some herbs lower blood pressure or alter drug levels | Discuss with your doctor |
| Sedatives, sleep or anti-anxiety medicines | Ashwagandha, brahmi and others can add drowsiness | Avoid combining without advice |
| Immunosuppressants or autoimmune treatment | Immune-stimulating herbs (ashwagandha, giloy) may interfere | Avoid unless your specialist agrees |
| Chemotherapy or cancer treatment | Herbs can alter drug effects or liver function | Only with your oncology team's agreement |
Always tell both your Ayurvedic physician and your regular doctor about everything you take, including supplements. Stop herbs before planned surgery as advised by your surgeon.
Independent laboratory studies have found that a subset of unregulated Ayurvedic products, particularly mineral/metal preparations sold outside regulated channels, contained unsafe levels of lead, mercury or arsenic. Plant-only products can also be mislabelled or adulterated. Practical steps:
At a reputable centre, herbs are one part of a plan that includes diet, routine and therapies such as Abhyanga, Shirodhara and, where indicated, Panchakarma. The doctor chooses herbs after assessing your digestion and condition, and reviews them as you progress. See the complete guide to Ayurvedic treatment in Kerala for how programs work, and Ayurvedic diet 101 for the food side.
They are plants (and, in some traditional preparations, minerals) used in Ayurveda as medicines, foods and tonics. A physician normally selects, combines and doses them to suit the individual's constitution and condition.
Many are used safely, but they are active substances. They can interact with medicines, some are unsafe in pregnancy, and unregulated products have been found contaminated with heavy metals. Use physician guidance and reputable products.
Evidence is strongest, though still limited, for ginger (nausea), some trials of ashwagandha (stress and sleep), and turmeric/curcumin (osteoarthritis pain). For most herbs the evidence is small or mainly traditional.
Not automatically. Herbs can interact with blood thinners, diabetes, thyroid, blood-pressure, sedative and immunosuppressant drugs. Tell your doctor and pharmacist what you take before starting.
Many herbs are avoided in pregnancy and breastfeeding. Only use them under the guidance of a qualified physician, and tell any practitioner that you are pregnant or trying to conceive.
Churna is a dry powder, kashayam is a decoction boiled from herbs, and taila (thailam) is a medicated oil made by cooking herbs in oil, used mainly externally.
Plant-based preparations generally do not by design, but some mineral/metal (bhasma, rasa) preparations are made with metals, and unregulated products have tested positive for lead, mercury or arsenic. Use prescription-only, regulated products from reputable manufacturers.
It depends on the herb, dose and the person. Some are used for weeks to months under guidance, but long-term safety data are limited for many, so have your physician review your use periodically.
Usually yes. Some herbs affect bleeding, blood sugar or anaesthesia. Tell your surgeon about all supplements and follow their advice on when to stop.
From a qualified Ayurvedic physician or a regulated centre, or from established GMP-certified manufacturers. Be cautious of unbranded products sold online with miracle-cure claims.