RR is a flower essence, operates at a subtle level and is very very gentle. It is not like other herbal tinctures in that respect. All the flower essences are more or less like homeopathic remedies in being subtle, gentle and totally non-harmful--even if it didn't help, the herbs would not hurt you at all. There is really *no* contra-indication, no toxicity level. Take it at need--even every 10-15 min. for an hour or even more, during any shaky or upset time. It does work fast, no need to anticipate it's use.