Another popular treatment of humoral deficiency was to restore the equilibrium by depleting the other humours which would now be present in relative excess.
Purges would result in diarrhoea and a depletion of black bile. Emetics would cause vomiting and reduce the yellow bile.
Blistering caused by the application of irritative salves to the skin was thought to alter the humoral balance. Blood letting of course would reduce the amount of the dominant humour.
Bleeding with lancets and leeches became increasingly popular in the 18th and and 19th centuries. A remarkable success story for a procedure which was at its best either ineffective or harmful (unless you happened to have haemochromatosis, polycytheaemia or heart failure).
Because of the profound physical manifestations of the treatment it is likely that all these methods had a very significant placebo effect. They were heap big medicine for the patient.