Well perhaps I should have been clearer. What I meant with things not being simple is that there are surprising side-effects of some drugs/supplements that actually result in the good effects. Because there are people who don't have heavy metal toxicity, but still benefit from taking DMSA, because of its undocumented effects. This issue of undocumented effects of DMSA is being debated in the autism community I think, because mercury chelation alone cannot explain all the positive effects of DMSA (some do not excrete mercury when using DMSA, but still see improvement). Since everyone with chronic illnesses have pathogens (I think this is a reasonable assumption), it is reasonable to think the side-effects have something to do with them, and that it is the pathogens that cause most, if not all of the harm. They are also something one can detect, if bothered about. For some reason mainstream doctors are not interested in these issues (detecting chronic pathogen infections).

The best explanation for what mercury causes is immunomodulation, making the body neglect the intracellullar pathogens (expect chronic viral infections, and intracellular bacterias) This negative effect of mercury usually clears within a few days after all the fillings have been removed, and then you have the burden of removing these infections. So amalgam removal is still necessary of course. In more difficult cases, amalgam removal is not enough, however. Trevor Marshall mentions the possibility of some pathogens causing abnormal levels of some vitamin D forms in body, which causes immunosuppression.

I think it is entirely reasonable to say that the combination of ALA+DMSA is aimed at pathogens, ALA in particular (according to my own experience). But going too much focused on the mercury leaves also other important issues unresolved. Ammonia detoxification is one issue that is rarely spoken about here, but I found myself that it is very important. Too often people leave this forum brain-fogged, and mentally fatigued after they think they are ok enough. This too can be addressed with correct supplements, those which Andy does not talk about.