During the febrile paroxysm, which lasts up to a week, light fluid diet only can be taken. The tendency to collapse at the time of the crisis renders it necessary that nourishment be systematically administered. Towards the end of the fifth or sixth day when the crisis may be expected, stimulants are necessary, and may have to be given in large quantities if marked collapse occurs.

The jaundice, so common during the attack, will disappear spontaneously; the critical diarrhoea, though often dysenteric in character, will also subside soon after the crisis. When purging ceases, ordinary light diet may be resumed till the next febrile attack. Constipation, as well as vomiting, usually precedes and is associated with the onset of the fever, so that towards the time when relapse is due a return to fluid diet is indicated.