Single-cell microorganisms, or microbes, found in plants that can cause intestinal distress and damage to the immune system if not kept under control. Most cannabis regulations require producers to test for total microbials and severely limit the amount available in the final form. The most commonly tested microorganisms include, but are not limited to, Escherichia coli (E. coli), salmonella, aspergillus, and any fungus.

E. Coli and salmonella are microbials.

Cannabis that has been contaminated with microbials are potentially harmful.