Warning issued over dangerous ‘Rainbow Shot’ kratom tea blends

Following the decriminalisation of kratom from Category 5 narcotics under the Narcotics Act 2021, Thai citizens are now allowed to brew kratom tea for personal consumption within their households without legal repercussions. 

However, the commercial production and sale of kratom tea remain regulated, requiring prior authorisation from the Food and Drug Administration (FDA). 

Authorities continue to crack down on unauthorised distribution, particularly as many such products have been found to contain harmful additives.

At the recent National Conference on Health Product Consumer Protection 2025, held under the theme "Digital Economy Challenge for Sustainability", the FDA presented research highlighting the growing misuse of kratom tea in Thailand’s Health Region 5. 

The study, titled “Misuse of Medicinal Syrup Mixed with Confiscated Kratom tea in Health Region 5 (FY2021–2025)”, was conducted by Tuangporn Khemthong, Prinya Mapradit, and Natcha Kaewwonglom from the Medical Sciences Centre Region 5, Samut Songkhram.

The research revealed a shift in law enforcement trends since kratom’s legal status changed — from arresting individual users to targeting unauthorised sellers. Investigations also found that many kratom brews were mixed with medicinal syrups, such as antihistamines or cough medicine, or that syrups were sold alongside kratom tea for consumers to mix themselves. This behaviour potentially violates the Drug Act 1967.

The misuse of syrup-laced kratom tea is particularly widespread among young people and manual labourers in Region 5. 

When mixed, the concoction can affect the central nervous system, leading to drowsiness, confusion, and even loss of consciousness. It poses a serious risk of accidents, particularly among those operating vehicles or machinery. 

The sweet taste of the syrup may also increase the likelihood of repeated use and addictive behaviours, raising public health concerns.

As demand for medicinal syrups has increased—despite strict regulations on their sale in licensed pharmacies—there has been a rise in the illicit production of counterfeit products lacking the active pharmaceutical ingredients declared on their labels. 

The misuse of these syrups, especially when mixed with kratom tea, poses a significant threat to public health and safety. It also constitutes violations of several laws, including those governing pharmaceuticals and consumer protection.

This study plays a vital role in monitoring trends in the misuse of health products and aims to propose suitable systemic solutions at the local level.

It is a descriptive research project based on secondary data obtained from government agencies, as well as a review of relevant academic and legal literature.

The study analysed confiscated samples of kratom decoctions and medicinal syrups collected by authorities in Health Region 5, which includes Suphan Buri, Nakhon Pathom, Kanchanaburi, Ratchaburi, Samut Songkhram, Samut Sakhon, Phetchaburi, and Prachuap Khiri Khan. A total of 778 samples were examined between October 2020 and May 2025.

Of these, 482 samples (61.95%) were kratom decoctions, 272 samples (34.96%) were medicinal syrups, and 24 samples (3.09%) were syrup-like products falsely labelled as dietary supplements or syrup-based drinks.

Among the kratom decoction samples, Diphenhydramine was detected in 123 samples (25.52%), Chlorpheniramine in 99 samples (20.54%), and a combination of both substances in 37 samples (7.68%). Notably, no samples tested positive for codeine or other narcotics.

The most commonly used medicinal syrups mixed with kratom decoctions contained either Diphenhydramine (161 samples or 59.19%) or Chlorpheniramine (111 samples or 40.81%). Of these, 264 samples (97.06%) had valid registration numbers. 

However, 12 of the samples (4.55%) were found to be counterfeit—lacking the listed active ingredients—and 8 samples (2.94%) had been repackaged into unlabelled squeeze bottles, presumably to avoid detection.

Arrest records related to kratom decoctions and medicinal syrup misuse in fiscal year 2021 revealed 60 cases involving consumers, with 87 samples seized. 

At that time, the seized substances were typically stored in aluminium pots or ice buckets, suggesting small-scale, household-level consumption.

In fiscal year 2022, enforcement was in a transitional phase due to evolving legislation, resulting in only five samples submitted for testing and no offender data recorded.

From fiscal year 2023 onwards, enforcement patterns shifted significantly towards targeting unauthorised sellers. 

Confiscated items were packaged in transparent plastic bottles—ready for sale—in quantities ranging from 600 millilitres to 1.5 litres. 

That year, 192 cases involving Thai nationals were recorded, with 602 samples seized, alongside 59 cases involving Myanmar nationals, with 84 samples confiscated.

By fiscal year 2024, the issue had spread beyond the previously affected provinces of Phetchaburi, Prachuap Khiri Khan, and Samut Sakhon. 

Notably, authorities began to detect more sophisticated products, including those modified for appeal with colour, scent, and flavour—known as “rainbow shots.” 

This variant was first identified in Nakhon Chai Si district, Nakhon Pathom province, in fiscal year 2025.

The study of seized samples from Health Region 5 between 2021 and 2025 confirmed widespread mixing of medicinal syrups—particularly those containing diphenhydramine and chlorpheniramine—with kratom decoctions. 

The nature of the offence has evolved from individual consumption to increasingly commercialised and complex practices, including product manipulation, counterfeit production, and repackaging to evade detection. 

These developments highlight the growing challenges of local-level health product regulation.

To address the issue effectively, a systemic and proactive approach is needed. This should include strengthened surveillance, improved data sharing across agencies, public risk communication, and greater community engagement. Such measures are vital to mitigate the long-term health risks and ensure sustainable consumer protection.