I have posted before about Jarisch-Herxheimer reaction (JHR or ‘herx’) reactions,
I have had months of herx reactions before two remissions and learn to control it. By control, I mean keep the amount and duration of herx in a comfortable range occurring at the times that I wish it to happen. This is not easy to do with mental fog. I am currently chatting daily with someone that is going thru a herx and additional supplements are arriving that they wish to add. Some of these new supplements are poor choices when you are already herxing hard. The herx has been severe for her, she has had to crawl to the washroom (like my own wife did for her CFS some 15 years ago). One of her characteristics is depression and anxiety – which is very common in CFS (even without a herx!)
How long will it last?
From when you take something until it is at peak concentration in your body is the time that the herx will slowly increase. Typically it is 2-3 hours (see table below). This is why I usually suggest taking antibiotics/antivirals about 1-2 hours before bed so the herx hits in your sleep (or helps you get to sleep).
The half life is the time until the herx or effect decreases by 50%.
- Lactobacillus/Bacilus/Bifidobacteria probiotics ~ 12 hrs
- E.Coli / Entercoccocus probiotics -12 weeks
- You are taking minocycline and want to increase the herx and have a choice of NAC or EDTA
- With NAC, you would take both at the same time and the herx will likely stay more severe for 6 hrs and then start to fade away – why because NAC half life is 6 hrs.
- With EDTA, you would take it about 3 hours after the minocycline. Because it has a short half life, you want the minocycline concentration to be at it max first.
If you are taking prescription antibiotics or antivirals, you will likely be able to find the time to peak and/or half life on pubmed. Click this link and change “antibiotic” to the specific antibiotics. http://www.ncbi.nlm.nih.gov/pubmed/?term=(MaxT+or+Half-Life)+and+antibiotic
The items do not directly impact infections, but they either breaks down protective films around infections (biofilms) or increases the penetration of antibiotics. If the herx is waning, taking some of these will likely increase herx. The increase of herx will dependent on the volume taken.
- Garlic (also increases histamines)
The classic way of decreasing herx is reducing the dosage. However, there are items that can reduce the herx -many of these items has the potential of inducing a secondary herx, however, I am not aware of that being reported for any on the lists. The lists are not comprehensive.
- Cetirizine (Zyrtec)
- A list of 37 herbals is here, when possible use as a tea
- Indian Long Pepper
- Anti-inflammatory – this is a short list containing only those with anti-depression effects and anti-stress effects (adaptogen).
Detoxification herbs are a model advocated by alternative medicine. These are herbs that assist with removing toxins from the body, conceptually, the toxins producing the herx. When I checked PubMed, I found just over 50 articles, it is very understudied. I came across this in the Journal of Alternative Complementary Medicine:
“Whereas supplements for which good supporting evidence exists generally cost around $3-$4 per month, those that are heavily promoted for which there is little supporting evidence cost about $20-$60 per month. The major cause of this problem in the United States is weakness of the law. There is an urgent need for stricter regulation and for giving better advice to the general public.” 
- LICORICE: A protective mechanism of licorice (Glycyrrhiza uralensis): isoliquiritigenin stimulates detoxificationsystem via Nrf2 activation.
- Synergistic anti-inflammatory effect of Radix Platycodon in combination with herbs for cleaning-heat and detoxification and its mechanism.
- Turmeric/Curcumin: Curcumin activates defensive genes and protects neurons against oxidative stress.
Honestly, who actually knows! If the herb kills some groups of bacteria (and most do), you may get additional herxing. IMHO, once you are herxing, you should keep your supplements the same — with CFS there is not only brain fog, but also response to supplements fog!