['Many Americans have heartburn or related symptoms monthly and >20% experience heartburn at least once per day. Although many self-treat episodic heartburn with nonprescription antacids, newer treatments that decrease gastric volume and increase the pH of refluxed material are proving effective and popular in relieving heartburn.', 'To evaluate the safety and efficacy of low-dose regimens of ranitidine for the relief of heartburn.', 'Adults with at least a 3-month history of heartburn were eligible for this randomized, double-blind, parallel group, multicenter dose-ranging study. Following a 1-week, open-label run-in phase to document baseline heartburn frequency, subjects were randomly assigned to receive treatment with one tablet of either ranitidine, 75 mg (n = 537); ranitidine, 25 mg (n = 539); or placebo (n = 544), to be taken as needed up to four times daily for 2 weeks for the relief of heartburn.', 'The ranitidine 75-mg regimen was statistically (P < 0.05) and clinically (as defined a priori as > or =10% improvement) more effective than placebo in relieving episodic heartburn and in reducing antacid consumption. Ranitidine, 25 mg, was also statistically superior (P < 0.05) to placebo in providing heartburn relief. In addition, both regimens were superior to placebo in providing heartburn relief within 30 to 45 minutes of dosing. Ranitidine continued to be as effective over placebo in the treatment of the last heartburn episode as in the treatment of the first heartburn episode. Ranitidine was also equally effective over placebo in the treatment of mild, moderate, and severe episodes of heartburn. Ranitidine, 75 mg, was statistically superior to placebo for the relief of nocturnal heartburn episodes, whereas ranitidine, 25 mg, was not. All treatments were well tolerated and adverse events occurred no more frequently with the ranitidine regimens than with placebo.'] Are nonprescription doses of ranitidine effective in the relief of episodic heartburn?