General Approach: This study proposes to compare sublingual 0.4 mg doses of nitroglycerin to placebo for initial treatment for acute pain from suspected symptomatic cholelithiasis. Patients with right upper quadrant abdominal pain of less than 24 hour duration between ages 18 and 60 years of age will be offered treatment with sublingual nitroglycerin or placebo. Patients with obstructive hypertrophic cardiomyopathy, pronounced hypovolemia, STEMI or presumed cardiac chest pain, inferior myocardial infarction with right ventricular involvement, raised intracranial pressure, cardiac tamponade, and patients taking certain drugs for erectile dysfunction (phosphodiesterase inhibitors), pregnancy, or with a known allergy to nitroglycerin will be excluded from the study.