Genova Diagnsotics just started subtyping Blastocystis, should that matter to clinicians? It might. Blastocystis is a unicellular eukaryotic microorganism that has extensive genetic diversity, and is often identified as the most common organism reported in human fecal samples. Blastocystis sp. are assigned to one of nine subtypes. It is not currently clear if Blastocystis is considered a pathogen, a commensal or even a beneficial member of the human gut microbiome. Many people who are positive have no symptoms, but for others it is a frequent cause of gastrointestinal symptoms. Blastocystis from different hosts are morphologically very similar, yet display substantial genetic variability: There are 17 different subtypes (STs), nine of which (ST1 to ST9) are associated with human colonization. In a healthy human cohort (n = 50) the most common STs of Blastocystis were ST1 to ST4, and mixed infections were found in 22% of the cases. Results have shown that certain STs occur predominantly as either single (ST3 and 4) or mixed (ST1) infections. Eradication of Blastocystis is sometimes essential such as when it is the only infectious agent and there are significant symptoms, but in other cases it is not. Currently, metronidazole (MTZ) has been the drug of choice. Unfortunately, MTZ’s efficacy has been relatively low. Identifying what specifically what is in the gut can help better target treatments. Some literature has shown that garlic, ginger, some medical plants, and many spices may help in the eradication of blastocystis by inhibiting parasitic enzymes, nucleic acids, and protein synthesis. Each of the Blastocystis sub-type may be affected by treatment differently.

Below are a few possible plant compounds identified by Lepczyńska, et. al. (2017) that may act against Blasto:

  • STs 1, 3, and 5 were susceptible to metronidazole (MTZ), but did encounter resistance.
  • STs 1 and 3 were not sensitive to ginger, black pepper, or cumin, compared to garlic and MTZ. Garlic (Allium sativum) contains a wide range of the thiosulfinates (e.g., allicin), which are responsible for the antibacterial activity.
  • ST 3 was inhibited by Ferula asafetida (oleo gum resin in both powder and oil form).
  • ST's 1, 2, and 3 were impacted by yarrow (Achillea millefolium) which acted as an anti-protozoal agent
  • Supplementation with 600 mg emulsified oil of Mediterranean oregano (Origanum vulgare) daily lead to the complete disappearance of Blastocystis.
  • Saccharomyces boulardii has also been shown to be effective against Blastocystis.


  1. Ann Agric Environ Med. 2018 Sep 25;25(3):411-416.
  2. Appl Environ Microbiol. 2015 Jun 15;81(12):4071-6.
  3. Ann Agric Environ Med. 2018 Sep 25;25(3):411-416.
  4. Ann Agric Environ Med. 2018 Sep 25;25(3):411-416
  5. Lepczyńska, et. al. Eur J Clin Microbiol Infect Dis (2017) 36:1531154.