this topic comes up quote a bit - and its often observed that it what we experience doesn't always fit with the common explanation ie that its caused by toxins released when you kill bacteria with antimicrobials ( pharma or herbs )
this article from Dr Jernigan at the Biologix centre gives a slightly different explanation for it -
he claims this debunks previous theories - i'm not sure i would go that far - but i did find it interesting
so i thought was worth posting in case others are interested
his theory is that it is caused by bacteria that have been exposed to antibiotics and are incapacitated but still live, and are then engulfed by patrolling white blood cells - and before they are digested by the white cells these still live bacteria trigger the white blood cells to release large amounts of inflammatory cytokines which in turn drive the herx like reactions.
Note - he is using this as part of a marketing strategy for his Phage based therapies - which he claims do not have this effect - so, since there is a financial incentive to tell us thing that may not be true, we would do well to seek independent confirmation.
https://biologixcenter.com/herxheimer-reactions/herxheimer-reaction-cause-debunked-as-new-research-reveals-true-causes/?fbclid=iwar3qhibbe1an-zptfwtxrvwabggl-mlystyz9lhic8wwl6qsbg1m6patjgs