OBJECTIVE: The use of colchicine to prevent acute gout flares during initiation of allopurinol therapy is widely practiced despite lack of proven benefit. We investigated if colchicine administration during initiation of allopurinol for chronic gouty arthritis reduces the frequency and/or severity of acute gout flares. METHODS: Patients starting allopurinol for crystal-proven chronic gouty arthritis were randomized to receive colchicine 0.6 mg po bid or placebo in a randomized, prospective, double blind, placebo controlled trial. Subjects were followed for evidence of acute gout flares and remained on study drug for 3 months beyond attaining a serum urate concentration < 6.5 mg/dl. Treatment arms were analyzed regarding frequency of flares, likelihood of any flare or multiple flares, severity of flares on the visual analog scale (VAS), and length of flares in days. RESULTS: Forty-three subjects were studied. Subjects treated with colchicine experienced fewer total flares (0.52 vs 2.91, p = 0.008), fewer flares from 0 to 3 months (0.57 vs 1.91, p = 0.022), fewer flares 3-6 months (0 vs 1.05, p = 0.033), less severe flares as reported on VAS (3.64 vs 5.08, p = 0.018), and fewer recurrent gout flares (p = 0.001). Colchicine was well tolerated. CONCLUSION: Colchicine prophylaxis during initiation of allopurinol for chronic gouty arthritis reduces the frequency and severity of acute flares, and reduces the likelihood of recurrent flares. Treating patients with colchicine during initiation of allopurinol therapy for 6 months is supported by our data.