The urinary excretion rates of nitrate (NO3) and nitrite (NO2) were mo
nitored in 14 patients with active ulcerative colitis during treatment
using hydrocortisone and sulfasalazine. During the active phase of th
e disease, the NO3 excretion was significantly higher in the patients
than in healthy controls (n = 6, p < 0.05), although it varied conside
rably among the patients. During the healing phase, the NO3 excretion
decreased concurrently with improvement of symptoms and colorectal ulc
eration, but the NO2 excretion increased. During the inactive phase of
the disease, the NO3 and NO2 excretions were significantly lower than
during the active phase, and the NO2/NO3 ratio resembled that in the
healthy controls. In contrast, a patient who failed to respond to trea
tment showed continuously high NO3 and NO2 excretion rates. These resu
lts indicate that urinary NO3 and NO2 excretions vary with the disease
state in ulcerative colitis.