interesting. I have a feeling there's something important to this. I'd forgotten that Andreas said that, and it was on his forum that I first heard of this practise. In the past few days I've been doing it about ten minutes, and Have experienced a lot of feelings of autointoxication...strange headache and this morning, woke for the first time in my life with what I've always heard others describe as 'flu': awful stomache cramps, loose bowels. Did the oil swishing again, ten minutes, and then did a salt water flush, which really helped. Twenty minutes does seem like an awfully long time-- I agree, intuition would say, this is long enough for toxins to be reabsorbed. I guess the only way they wouldn't would be that something in the oil will allow a 'pulling' but perhaps not a 'pushing'(?) so to speak.
My diet is almost pure vegan, no coffee, etc. so I would not think I am abnormally toxic. Still, twenty minutes sounds like a lot of "pulling".