Cannabis extracts show significant antifungal and antibacterial effects

Bacteria and fungi are increasingly developing resistance to traditional antimicrobial treatments. This study tested the antimicrobial properties of 5 cannabis extracts. It was published online ahead of print in July 2023 in the Journal of Ethnopharmacology.

This in vitro (using lab cultures) study is of particular interest because in practice, humans often apply antimicrobial topical solutions (lotions, creams, soaps, etc.) to help control or eliminate bacteria, fungus, and yeast on themselves and their environment.

The study included 4 types of bacteria:
  • Bacillus thuringiensis (Gram +)
  • Escherichia coli (Gram -)
  • Micrococcus luteus (Gram +)
  • Pseudomonas protegens (Gram -)
One type of yeast:
  • Saccharomyces cerevisiae
One type of fungal spores:
  • Fusarium eumartii


They used ethanol extraction to create "resin" from the 5 different cannabis flower cultivars (full spectrum). 4 were THC dominant, and 1 was a balanced THC:CBD flower. The THC dominant cultivars had THC amounts ranging from 13% to 39%. They did their own testing with HPLC and Gas Chromatography to determine cannabinoid and terpene content of the flowers. The balanced cultivar had a 1:1 THC to CBD ratio of 7.5% each.

All extracted resins were diluted with dimethyl sulfoxide (DMSO) to have the same concentration of the resin (1ug/ul). Pure DMSO was used as the control solution.

Simple results summary:

  • Bacillus thuringiensis - balanced THC:CBD extract reduced growth by over 95% at the intermediate concentration (2ug/ml) and slightly less than 95% at the maximum concentration (4ug/ml).
  • Escherichia coli - All extracts were able to reduce growth by over 80%, albeit at different concentrations.
  • Micrococcus luteus - balanced THC:CBD extract reduced growth by over 90% at the intermediate concentration, but only around 80% at the maximum concentration.
  • Pseudomonas protegens - none of the extracts worked very well. The balanced extract worked best and reduced growth by about 20% at the maximum concentration. Since this bacteria is a well-known plant-protecting bacteria, it seems logical that a plant-derived extract might not be effective.
  • Saccharomyces cerevisiae - all extracts reduced growth by over 90% at 0.25ug/ml and 1ug/ml concentrations, however 0.5ug/ml reduced growth by only about 80%.
  • Fusarium eumartii - growth was almost completely stopped in all extracts at concentrations above 0.15ug/ml
Below is the chart for Bacillus thuringiensis showing that the balanced THC:CBD extract (C5) worked best, and at a concentration below the maximum concentration tested:
    Bar chart showing the differences in bacillus thuringiensis bacteria growth versus control. An intermediate concentration of 2ug/ml of balanced THC:CBD extract (C5) worked best (95+% growth reduction), even better than a concentration of 4ug/ml.


    General observations:

    • The balanced THC:CBD extract worked best on all bacteria and fungal cultures.
    • All extracts reduced yeast growth by over 90% at an intermediate (2ug/ml) and maximum concentration (4ug/ml)
    • ONLY Pseudomonas protegens did NOT show a similarly significant reduction in growth at the maximum concentration
    • The THC % of the original flower was NOT correlated with increased effectiveness (higher THC wasn't better)
    • Microbial growth of several cultures was most inhibited at an intermediate concentration, NOT the maximum concentration. This alludes to a "best dose" that is NOT the maximum concentration (more isn't better).


    The authors concluded:

    All cannabis varieties were effective to different degree against Gram (+) and Gram (−) bacteria as well as on spore germination and vegetative development of phytopathogenic fungi.

    These effects were not correlated to the content of major cannabinoids such as CBD or THC, but with the presence of a complex terpenes profile.


    The abstract and some article "snippets" are here at



    Antifungal and antibacterial activities of Cannabis sativa L. resins.,
    Journal of Ethnopharmacology, Volume 318, Part A, 2024, 116839, ISSN 0378-8741

    María Eugenia Vozza Berardo, Julieta Renée Mendieta, María Daniela Villamonte, Silvana Lorena Colman, Débora Nercessian,