Professor Edzard Ernst, in the third paragraph, says a slight headache and a low probablilty of stroke means you should not go to a chiropractor for your back.
But in the same paragraph he did not condemn chemotherapy which has a high probability of both (headaches & stroke). (..and innumerable blood clots, something not causd by the chiropractor..)
definition for whom its usefull:
innumerable...not able to be numbered
..............countless
..............numerous