Siang Pure Oil (ยาหม่องสยามภัณฑ์) — The Thai Inhalable Medicated Oil from Bertram Chemical

Walk into any 7-Eleven in Bangkok, any pharmacy in Chiang Mai, or any souvenir stand at Suvarnabhumi Airport and you will see the same little triangular glass bottle stacked behind the counter — amber liquid, red-and-yellow label, cap shaped like a tiny pyramid. Siang Pure Oil (Thai: ยาหม่องสยามภัณฑ์ / ya mong sayam phan) is the medicated oil that Thai grandmothers carry in their handbags, that monks tuck into the folds of their robes, and that taxi drivers keep clipped to the dashboard for traffic-jam dizziness.

Outside Thailand it is one of the most recognisable Southeast Asian “smelling oils,” exported across ASEAN, the Middle East, and increasingly to Western wellness markets — but its identity is firmly Thai-Chinese, traceable to a single immigrant herbalist who learned a Shantou (Teochew) formula in the late 1950s and built an empire around it. This guide covers where Siang Pure came from, what is in the bottle, how Formula I and Formula II differ, and how to use it without overdoing it.

Origin: Master Tang, Boonchua, and the Shantou formula

The Siang Pure story begins not in a laboratory but in a Bangkok shop-house in the late 1950s. Boonchua Eiampikul, an ethnic-Chinese Thai of Teochew descent, apprenticed under a Chinese-medicine practitioner named Master Tang. Master Tang shared a herbal formula traditionally used in the Shantou (汕頭) region of Guangdong for relieving dizziness, fatigue, and “wind” symptoms. Boonchua refined the formula into an oil-based product — easier to carry, easier to inhale — and began selling it in small quantities to the Chinese community in Bangkok. It sold out almost immediately.

To formalise production, Boonchua established Chakrintr Ltd. Partnership in 1963. The business was renamed Bertram Chemical Works Ltd. Partnership as it relocated to a more central Bangkok location, and as the oil’s popularity spread to Laos, Cambodia, Myanmar, and Malaysia, Boonchua’s three daughters joined the business. In 1982 the company took its modern name: Bertram Chemical (1982) Co., Ltd. That date is now part of the brand identity — the corporate parent today markets itself as Bertram 1958, anchoring the year Boonchua learned the formula as the brand’s symbolic founding.

By 2007 Siang Pure held roughly 80% of Thailand’s herbal-oil market, and by 2008 the company was generating annual sales of around 330 million baht with 140-plus employees. To prevent the brand from becoming what its own marketing literature called “a frumpish product mostly used by the elderly,” Bertram launched the spin-off Peppermint Field line in the 2000s, targeted at younger urban consumers — but the core Siang Pure Oil bottle remains essentially unchanged from the 1960s shape.

The herbs that go into the bottle still come, where possible, from Shantou. Bertram’s stated reason for importing peppermint, camphor, clove, menthol, borneol, and cinnamon from the Pearl River Delta is fidelity to the original formula — the same logic that keeps Pak Fah Yeow’s white-flower oil tied to its Singapore-Hong Kong supply chains.

What is actually in the bottle

Siang Pure Oil is sold in two formulas, and the difference is genuinely meaningful — not just marketing. Both are concentrated essential-oil blends in a light mineral-oil carrier, but the herb ratios produce noticeably different sensory and clinical profiles.

Formula I (amber / red label)

The original. Roughly 86% active ingredients, dominated by:

The result is a strong, herbal-spicy aroma that opens the sinuses immediately. Thai users typically reach for Formula I when they want the biggest possible olfactory hit — for fainting spells, bus-trip nausea, or shaking off post-lunch drowsiness.

Formula II (clear / green label)

Reformulated in the early 2000s for users who found Formula I too pungent. Roughly 82.5% active ingredients, but with the cinnamon and clove dialled down and the peppermint and menthol leading. The colour is essentially water-clear; the scent is cleaner, cooler, and more “modern.”

Formula II is what Thai office workers and younger consumers tend to pick. It is also the version most commonly sold with a ball-tip applicator (5 cc roller bottle), which makes it easier to dab onto temples and pulse points without overdosing the skin.

Both formulas are licensed by the Thai FDA as a registered medicinal product (not a cosmetic), and both carry instructions for inhalation as well as topical use.

The Siang Pure family: not just the oil

Although the amber bottle is the icon, the Siang Pure brand has expanded into a full medicated-oil ecosystem. The lineup now includes:

For travellers and beginners, the entry point is almost always Formula I oil in 7 cc or Formula II ball-tip 5 cc — the two bestselling SKUs in convenience-store format.

How Thai users actually use it

Siang Pure Oil’s defining trait, more so than Tiger Balm or White Flower, is that it is used as much for inhalation as for topical application. The triangular bottle is designed to be unscrewed and held under the nose; the menthol-camphor-eucalyptus vapour acts on the trigeminal nerve to produce a “wake-up” sensation almost instantly.

Inhalation use — the primary mode

Topical use

Pulse-point method (the ball-tip Formula II trick)

Because the ball-tip applicator delivers a measured micro-dose, modern Thai users frequently apply Formula II to:

This is the format most Westerners encounter and is generally the safest entry point for a first-time user.

Safety and where to draw the line

Siang Pure Oil is more concentrated than most household embrocations sold in the West, and the camphor and methyl-salicylate content of related Siang Pure products means a few hard limits matter.

Storage and authenticity

Siang Pure Oil should be stored tightly capped, away from direct sunlight, ideally below 30 °C. The amber colour of Formula I will deepen slightly over time even when stored properly; this is normal. Formula II, being clear, will yellow slightly with age — this is also normal but indicates the volatile aromatics are oxidising. As a rule, finish a bottle within two years of opening for maximum potency.

Counterfeits are a real problem in Southeast Asian markets. Genuine Siang Pure Oil bottles carry:

Buying directly from the Bertram1958 official store, from licensed Thai pharmacies (Boots, Watsons Thailand, Fascino), or from established Asian-grocery importers in your country is the safest route.

Where Siang Pure Oil sits among Asian medicated oils

If Tiger Balm is the muscle-and-joint brand, White Flower is the headache-and-sinus brand, and Yu Yee Oil is the infant brand, then Siang Pure is the inhalable wakefulness brand — a smelling oil first, an analgesic second. Its closest cousins in the regional market are Eagle Brand Medicated Oil (Singapore) and Imada Red Flower Oil (Hong Kong), both of which share the dual inhalation-and-topical use pattern.

For Western users discovering Asian medicated oils for the first time, Siang Pure Formula II in the ball-tip format is one of the gentlest, most travel-friendly entry points — and one of the few that captures, in a single small bottle, an unbroken 70-year line from a Shantou herbalist’s recipe to the present-day Bangkok skyline.

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