Background: To determine whether high doses of fish oil, administered over 2 weeks, improve symptoms in patients with advanced cancer and decreased weight and appetite. Methods: Sixty patients were randomly assigned to fish oil capsules or placebo. Appetite, tiredness, nausea, well‐being, caloric intake, nutritional status, and function were prospectively assessed at days 1 and 14. Results: The baseline weight loss was 16 ± 11 and 16 ± 8kginthe fish oil (n = 30) and placebo (n = 30) group, respectively, whereas the baseline appetite (0 mm = best and 100 mm = worst) was 58 ± 24 mm and 67 ± 19 mm, respectively (p = not significant). The mean daily dose was 10 ± 4 (fish oil group) and 9 ± 3 (placebo group) capsules, which provided 1.8 g of eicosapentaenoic acid and 1.2 g of docosahexaenoic acid in the fish oil group. No significant differences in symptomatic or nutritional parameters were found (p < .05), and there was no correlation between changes in different variables between days 1 and 14 and the fish oil doses. Finally, the majority of the patients were not able to swallow >10 fish oil capsules per day, mainly because of burping and aftertaste. Conclusion: Fish oil did not significantly influence appetite, tiredness, nausea, well‐being, caloric intake, nutritional status, or function after 2 weeks compared with placebo in patients with advanced cancer and loss of both weight and appetite.

Fish oil did not significantly influence appetite, tiredness, nausea, well-being, caloric intake, nutritional status, or function after 2 weeks compared with placebo in patients with advanced cancer and loss of both weight and appetite.