User:P2409
In general, I just make minor edits to pages that refer to pharmacological, toxicology or chemistry topics, trying to improve compound characteristics or medical references (my field). If the grammar in an article is particularly tortured or wrong, I will sometimes fix it up too, regardless of topic.
I also remove un-referenced, un-cited text in pharmacological or medical articles when they relate to sweeping, vague or sometimes plain incorrect clinical claims that are not backed up (i.e. correctly referenced and interpreted) in peer reviewed journal articles. My primary reference point for quality references is either The Cochrane Library or Medline (from the US National Library of Medicine). Low reputation commercial outfits trying to promote inadequately reviewed products for profit motivations is a bane of modern medicine (and Wiki unfortunately). I'm pleased to see Wiki editors pick this stuff up pretty quickly, and I do too when I find it!