Dietary supplements are the most popular class of complementary and alternative medicine (CAM) in Japan. In the present review, we describe several characteristics of dietary supplement users in patients with RA in Japan, based on our recent survey. Sixty percent of RA patients used supplements. Prevalence was higher in female than in male patients, and users were younger than non-users, particularly among females. These features were those found in CAM users in general. In comparison with CAM users with cancer, several specific characteristics of RA users emerged. First, the proportion of current users was significantly higher among those who had been diagnosed within the last 5 years compared with those who had been diagnosed more than 5 years ago, indicating that patients in the early years of disease were likely to use supplements. Second, RA patients preferred products made from herbs, algae or components of cartilage. This preference was different from that of cancer patients, who predominantly used mushroom-based products. Third, users expected CAM to produce ‘alleviation of symptoms’ and ‘health promotion’, indicating that the users expectations were essentially ‘complementary’. In contrast, cancer patients expected more positive and direct disease outcomes. Finally, we propose some ideas regarding the clinical significance of future dietary supplement use in RA, as orthodox therapeutic modalities greatly expand.