Small-bowel ulceration induced by potassium chloride.

achieved simply by stopping therapy until symptoms subsideusually in four to five days-and then resuming therapy gradually with increasing doses over several weeks. We have used n-pen. successfully now in two patients with welldocumented histories of penicillin allergy. Previously it was our belief that D-pen. would be effective only in preventing de novo stone formation or progression of stones already formed. Therefore patients with calculi and pyelonephritis-a complication we not infrequently encounterwere rendered stone-free surgically in order to maximize chances for eradicating infection with selected antibiotics. Our success in dissolving stones in each of these four patients has led us now to be more conservative in recommending operation to patients with nephrolithiasis complicated by pyelonephritis. So far we have not encountered any patient whose stones proved refractory to dissolution when D-pen. was added to the conventional programme.