Children and adolescents aged 6-17 years with symptomatic Bipolar I or II disorder (n=51), manic, hypomanic, mixed, or depressed, were randomized to either flax oil capsules containing 550 mg alpha-linolenic acid per 1 gram or an olive oil placebo adjunctively or as monotherapy. Doses were titrated to 12 capsules per day as tolerated over 16 weeks. Primary outcomes included changes in the Young Mania Rating Scale (YMRS), Child Depression Rating Scale-Revised (CDRS-R), and Clinical Global Impressions- Bipolar (CGI-BP) ratings using Kaplan-Meier survival analyses. Baseline and end-of-study free fatty acids were measured and examined for change and relevance to effect.