Carom Seeds (Ajwain): The Thymol Spice of Indian Cooking

Carom seeds, sold in India as ajwain, smell and taste like a louder, rougher thyme. There’s a simple reason: their oil is dominated by thymol, a compound also found in thyme oil. The “seeds” are the small, ridged fruits of Trachyspermum ammi, a plant in the carrot and parsley family. Most cooks use them by the pinch, fried in fat and poured over cooked lentils, and they turn up in Ethiopian berbere, too.

At a glance

What carom is

What’s sold as carom or ajwain seed is botanically a dried fruit, though it usually gets called a seed. Kew’s accepted name is Trachyspermum ammi, and it lists Carum copticum and Trachyspermum copticum among the plant’s 32 synonyms. That’s why older books and labels use several Latin names.¹ Katzer files the spice under T. copticum.³

The English names are a muddle. Katzer lists ajwain, ajowan, carom and bishop’s weed, and advises against “bishop’s weed” because other plants in the family go by that name too. Ajwain is also sometimes mislabeled as lovage seed, which is a different plant; see lovage. Katzer traces the Hindi name back to a Sanskrit word linked to “Greek.”³

Flavor and the compounds behind it

The aroma is similar to thyme but stronger and less subtle. Raw, the seeds are sharp and a little bitter, with a bite that lingers on your tongue.

The chemistry explains the thyme comparison. Thymol is a crystalline phenol with an aromatic smell and antiseptic properties, and it occurs naturally in thyme oil. In carom, it dominates the essential oil:

The review abstract names p-cymene, γ-terpinene, α-pinene, β-pinene and α-terpinene as thymol’s main companions, without percentages.⁴ These figures come from different samples and methods, so don’t merge them. For thyme itself, see thyme and oregano vs. thyme.

Origin and history

Where the plant comes from depends on who you ask:

Kew is the botanical authority on native range. The Egypt view shows up in the other two, and we couldn’t trace the evidence behind it. Kew lists the plant as introduced in places including Ethiopia, Saudi Arabia, Türkiye and Morocco. Katzer gives Persia and India as the main growing areas today and says ajwain matters little in world trade.³

Ajwain is used a lot in Ayurvedic medicine in India.³ You may read that it grew wild in ancient Egypt, was a common medicine there, or is used in traditional Chinese medicine. We couldn’t trace any of that, so we’ve left it out.

Production

India publishes the only production figures we found. The Spices Board of India gives ajwain seed at 65,018 tonnes from 63,147 hectares in 2024-25 (final) and an advance estimate of 68,505 tonnes from 63,050 hectares for 2025-26. Earlier years ran from 37,884 to 39,763 tonnes (2021-22 to 2023-24), so the 2024-25 crop was far bigger than the three before it. The Board notes that figures from 2020-21 on may be revised.² We found no world total.

How carom is used

• Lentils and beans. Katzer calls legumes the most important use. Ajwain is fried in fat, often with cumin and chiles, and the fat goes over cooked lentils (the tadka or baghar technique). He notes that most aroma compounds in spices dissolve much better in fat than in water.³
• Potatoes and fish. Toasting or frying makes the aroma stronger, and Katzer pairs it with potatoes and fish.
• Snacks and pastry. It flavors the Rajasthani biscuits called mathari, and similar pastries in Ladakh and Nepal.
• Beyond India. It’s in the Ethiopian spice mix berbere and has some following in the Arabic world. See berbere seasoning.

The flavor is strong, so most cooks use it by the pinch and cook it in fat first. Pair it with cumin, turmeric and ginger in lentil and vegetable dishes. For the bigger picture, see Indian spices.

Buying and quality

We didn’t find a grading standard for ajwain we could open. Look for whole, ridged seed without stems or dust that smells strongly of thyme when you crush it. Since ajwain is sometimes mislabeled as lovage seed, check that the label says ajwain or carom.

Storage

We found no shelf-life figure for carom seed from a regulator or standards body. Keep whole seed sealed, away from heat and light, and go by smell. Rub a few seeds between your fingers. If the thyme note is faint, the seed has faded. That’s a practical test, not a measured figure.

Safety and health claims

Katzer records traditional use of ajwain for digestive complaints and fever, and notes that thymol goes into Western medicines for cough and throat irritation.³ Britannica describes thymol as an antiseptic used mainly as a fungicide and preservative, and in perfumes and dentifrices.⁵ Those are uses of the purified compound. They say nothing about eating the seed.

A 2017 review sums up the biological and pharmacological properties reported for the plant, but its abstract doesn’t say whether that evidence comes from lab, animal or human studies.⁴ We found no NIH (NCCIH) page or systematic review of human trials for ajwain. You’ll often read that it treats arthritis, psoriasis, acne or respiratory illness, or that it preserves pickles. We couldn’t trace any of that to a credible source, and we’re not claiming carom treats or prevents anything.

Substitutes

Thyme is the closest flavor match because of the shared thymol, and dried thyme is the usual stand-in. Ratio (Method): Start with about the same volume of dried thyme and adjust to taste. See carom seed substitutes and thyme substitutes.