I stumbled across magnolia bark while looking for adaptogens.

Magnolia (Magnolia officinalis) is a medicinal plants commonly used as traditional remedies for reducing stress and anxiety. Effect of Magnolia officinalis and Phellodendron amurense (Relora®) on cortisol and psychological mood state in moderately stressed subjects[ ] found that it significantly lower salivary cortisol . It is also a relatively strong anti-inflammatory Identification of Magnolia officinalis L. bark extract as the most potent anti-inflammatory of four plant extracts[2013].  Magnolol treatment reversed the glial pathology in an unpredictable chronic mild stress-induced rat model of depression.[2013] confirmed its antidepressant-like effect.

Part of it’s mechanism is described in Magnolia polyphenols attenuate oxidative and inflammatory responses in neurons and microglial cells[2013] and helps with cognitive damage Honokiol protects brain against ischemia-reperfusion injury in rats through disrupting PSD95-nNOS interaction [2012] as well as helping memory  Ethanol extract of Magnolia officinalis prevents lipopolysaccharide-induced memory deficiency via its antineuroinflammatory and antiamyloidogenic effects.[2013]. Of special interest is its positive impact on memory Alzheimer’ (because some CFS SPECT scans appear similar to early Alzheimer) A Comparison between Extract Products of Magnolia officinalis on Memory Impairment and Amyloidogenesis in a Transgenic Mouse Model of Alzheimer’s Disease[2012]

For those with sleep disturbance, Magnolol, a major bioactive constituent of the bark of Magnolia officinalis, induces sleep via the benzodiazepine site of GABA(A) receptor in mice[2012].

It’s impact on gut bacteria is less well known, however it does appear to have impact on oral bacteria according to Effect of a sugar-free chewing gum containing magnolia bark extract on different variables related to caries and gingivitis: a randomized controlled intervention trial.[2011] and Compressed mints and chewing gum containing magnolia bark extract are effective against bacteria responsible for oral malodor[2007], Antimicrobial activity of magnolol and honokiol against periodontopathic microorganisms[1998-..  As well as some bacteria, Antimicrobial effect of Magnolia officinalis extract against Staphylococcus aureus.[2011] as well  Antifungal activity of magnolol and honokiol[2000]

Bottom line: This is definitely an excellent candidate supplement for CFS, especially when taken immediately after dinner as a potential assistance to sleep disturbances.