This double-blind controlled study investigated the effectiveness of 4% topical erythromycin liquid with 1.2% zinc acetate and 4% topical erythromycin gel with 1.2% zinc octoate applied twice daily in comparison with 250 mg of oral tetracycline twice daily and placebo. One hundred forty-nine patients began and one hundred forty-one completed the study. Three judges recorded acne measurements of severity grade, papule counts, pustule counts, comedo grades, and comedo counts without mutual consultation on visits at 0, 2, 4, 6, 8, and 10 weeks. Analysis of the reduction in the acne severity grade and papule count showed that the erythromycin/zinc liquid and gel were statistically significantly better than placebo and as effective as the oral tetracycline. Analysis of comedo grades showed that at weeks 8 and 10 the 4% topical erythromycin/zinc liquid showed a reduction statistically better than placebo.