To the Editor.—In discussing the treatment of ulcerative colitis, Dr Peppercorn1 states, "Sulfasalazine, mesalamine, and olsalazine have been proven to be effective in active ulcerative colitis," and he cites 3 studies. The first was a double-blind, placebo-controlled study by Dick et al2 using sulfasalazine and placebo pills. Clearly, it is impossible to blind a study using a placebo for sulfasalazine since nausea and headache are common early in the treatment when using sulfasalazine, and urine becomes a deep yellow-brown. The second study3 evaluated olsalazine against sulfasalazine. If sulfasalazine has not been proven effective, it hardly makes sense to compare it with olsalazine, unless one considers the former a placebo. The third study4 compared a coated oral 5-aminosalicylate agent preparation with a placebo. However, the adverse effects for the 4.8-g daily dose occurred in 55% of patients compared with 73% at a dose of 1.6 g daily and 61% for placebo. At best, the lack of dose response by rate of adverse effects, together with the high incidence of placebo adverse effects, raises questions about study validity.