The present study tested the long-term effects of the histamine (H) synthesis inhibitor alpha-fluoromethylhistidine (FMH) on feeding and body weight in rats. FMH (administered via 2-week osmotic minipumps) increased feeding significantly throughout the test period. Body weights were also significantly increased toward the end of the test period. Hypothalamic H assays, performed at the end of the study, confirmed that FMH-treated rats had significantly lower H levels than controls. In general, the results suggest that H activity and feeding are inversely related.