- Evaluation of the effect of a ginger extract (Zintona EC) on patients suffering from gonarthritis. Twenty-nine patients (6 men and 23 women) with symptomatic gonarthritis (ACR criteria), in the age range 42-85 years, were included after randomization in a double blind, placebo controlled, crossover study of 6 months' duration. The treatment group was given a ginger extract (250 mg of Zingiberis Rhizoma per capsule, qid), while the placebo group received the same number of identical looking capsules per day. The crossover occurred after 3 months of therapy. Results were evaluated by a 100mm visual analog scale (VAS) of pain on movement and of handicap. Eight patients dropped out because of inefficacy, three from group 1 (ginger extract first) and five from group 2 (placebo first). One patient from group 1 and one from group 2 dropped out because of heartburn (while they were on ginger extract). Twenty patients completed the study period of 24 weeks and 19 that of 48 weeks follow-up. By the end of 24 weeks there was a highly statistically significant difference between the VAS of pain and handicap of the two groups (P<0.001). However, at crossover both groups showed a statistically significant decrease in VAS of pain on movement and of handicap, but the differences between the groups did not reach statistical significance. Zintona EC was as effective as placebo during the first 3 months of the study, but at the end of 6 months, 3 months after crossover, the ginger extract group showed a significant superiority over the placebo group.