Identification and quantitation of the ingredients in a counterfeit Vietnamese herbal medicine against rheumatic diseases

•Brownish powder of cinnamon odor against rheumatic diseases purchased from the internet.•1H NMR and LC/MS revealed acetaminophen, trimethoprim, sulfamethoxazole and indomethacin as active pharmaceutical ingredients.•Cinnamon bark was identified by light microscopy.•Selling these sachets is illegal because it consists of prescription drugs.

Counterfeit and/or illegally manufactured drugs and herbal medicines are becoming an increasing problem throughout the world. Internet sales simplify distribution and payment of these falsified drugs. Here we report on a Vietnamese herbal medicine, which was advertised for treatment of rheumatic disease from a religious Vietnamese healer. By means of NMR and LC/MS we found 863 mg acetaminophen, 262 mg sulfamethoxazole, 42 mg indomethacin and less than 1% trimethoprim in a sachet of 2.617 g powder content, in addition to some cinnamon bark and phosphate.

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