Previous studies have shown that large doses of a urinary alkalinizing agent reduced cigarette consumption spontaneously among smokers. After establishing a safe daily dose of an alkalinizing agent, sodium bicarbonate, its effect upon smoking cessation rates among 72 enrollees in a smoking cessation program was studied. In the first study, we determined that sodium bicarbonate (3900 mg per day) significantly increased urinary pH (from 6.0 to 6.7) and lowered titratable acidity. Ascorbic acid (1500 mg per day) had no effect of pH or acidity. In a second study, a group given sodium bicarbonate surpassed a placebo control group (who were given 1500 mg per day ascorbic acid) in total daily cigarette reduction after 5 weeks and in week-to-week smoking reduction. The groups did not, however, differ in the number who achieved total abstinence.