Hi Ming Lie,
Toxicity refers to undesirable and harmful effects produced by an herb that is unintended for its therapeutic effect. Toxicity may occur from overdose or when a drug has a narrow therapeutic index; the difference in its effective dose and toxic dose is very narrow.
Apricot seeds contain a compound which is converted to cyanide in the body, which inhibits the brain’s respiratory centre, explaining its ability to relieve cough and asthma.
It is also used to relieve constipation because of its oily content. However, overdosing or consuming it over a long period of time may potentiate cyanide poisoning.
Currently, all the herbal medicine physicians prescribe to their patients herbal have to be in accordance with the principles and requirements recommended by the TCM Pharmacopoeia (中药药典).
Herbal prescription consists of several herbs that are combined together with the purpose of enhancing the herb’s properties /action (improve performance) and to decrease its toxicity (minimize any possible side effects).
Therefore, it is important to consult a trained and licensed TCM practitioner to take charge of your health issues, where herbs can be used under supervision.