Harmful microorganisms such as candida albicans, Escherichia coli, Staphylococcus aureas and Klebsiella pneumonia can protect themselves from antimicrobial agents such as certain herbs and antibiotics with a matrix called biofilms. Biofilms are complex groupings of microorganisms encased by a self generated mix of proteins, water, polysaccharides, debris and metals.
This may explain why certain people keeps falling sick despite doses of immune herbs and antibiotics (note:antibiotics actually increase population of harmful bacteria). This biofilm also protects cancer cells from the immune system and chemotherapy.
As a result, the harmful microbes that reside in the gastrointestinal tract can overtake the good bacteria which further compromise the immune function (note: immunity largely depends on a healthy gut). In addition, inflammation may results in chronic digestive disorders such as colitis, inflammatory bowel diseases etc.
I have started to use a class of specialized enzymes such as chitosanase and lysozyme to help break down the biofilm. This will be helpful for chronic allergies and candidiasis.