Background & Aims: Lymphocytic colitis is a common cause of chronic, nonbloody diarrhea. However, the effects of treatment are unclear and randomized placebo-controlled trials were requested in a Cochrane review. We performed a randomized, placebo-controlled, multicenter study to evaluate budesonide and mesalazine as induction therapy for lymphocytic colitis. Methods: Patients with active lymphocytic colitis were randomly assigned to groups given budesonide 9 mg once daily (Budenofalk granules), mesalazine 3 g once daily (Salofalk granules), or placebo for 8 weeks in a double-blind, double-dummy design. The primary endpoint was clinical remission, defined as ≤21 stools (including ≤6 watery stools), in the 7 days before week 8. Results: The final analysis included 57 patients (19 per group). Most patients were female (72%) and the mean age was 59 years. The proportion of patients in clinical remission at week 8 was significantly higher in the budesonide group than in the placebo group (intention-to-treat analysis, 79% vs 42%; P =.01). The difference in proportions of patients in clinical remission at week 8 between the mesalazine (63%) and placebo groups was not significant (P =.09). The proportion of patients with histologic remission at week 8 was significantly higher in the budesonide group (68%) vs the mesalazine (26%; P =.02) or placebo (21%; P =.008) groups. The incidence of adverse events was 47.4% in the budesonide group, 68.4% in the mesalazine group, and 42.1% in the placebo group. Conclusions: In a randomized multicenter study, we found oral budesonide 9 mg once daily to be effective and safe for induction of clinical and histologic remission in patients with lymphocytic colitis, compared with placebo. Oral mesalazine 3 g once daily was not significantly better than placebo. ClinicalTrials.gov no: NCT01209208.