On days 0 and 30 of a double blind study, two groups of 15 subjects each were evaluated using a plaque index, a gingival index, a gingival exudate flow and fasting plasma folic acid levels. Group I received 2 mg of folic acid twice daily for 30 days while Group II received a placebo. Results of the study seem to indicate that folic acid supplemented to the diet may increase the resistance of the gingiva to local irritants and thus lead to a reduction in inflammation.