The effects of ambient odor (lavender, neroli or placebo) and suggestions related to the effects of an odor (relaxing, stimulating or none) on mood were explored. Mood of 90 undergraduate women was assessed using physiological measures (heart rate and skin conductance) and the self-report Profile of Mood States questionnaire. Analysis indicated that physiological measures were influenced by suggestion in predictable directions. Relaxing odors yielded decreases in heart rate and skin conductance, with stimulating odors yielding the reverse effects under equivalent conditions. These data further support the notion that expectations play a significant role in mediating odor-evoked mood changes.