You should restrict consumptions on caffeinated drinks like coffee, strong tea and some soft drinks or you can consider decaffeinated options so to minimise the effect of caffeine on babies. You should avoid alcohol because of its adverse effect on health eg. affect judgment. Alcohol disrupts flow of breastmilk. It passes through breastmilk and may impair your baby's development. If you must drink on special occasions, make sure you limit your drinks to a small amount and avoid breastfeeding your baby within 2 hours.
Tonic food taken for general health would not affect breastfeeding. However, if it is a traditional herbal medicine, you should consult a registered Chinese medicine practitioner before taking.