[The use of herbal medicine therapies by cancer patients].

The use of herbal complementary and alternative medicines is growing among Portuguese cancer patients, contributing to a higher risk for unwanted interactions, especially due to the narrow therapeutic index of most oncolytic drugs. A literature review was carried out in order to determine which medicinal plants are most commonly used by cancer patients, in Europe and USA, and their risk of interaction with the multiple medications taken by those patients. The collected information reveals a high degree of herb-drug interaction suggesting that patients under antineoplastic treatments should avoid the concomitant use of herbal medicines. These findings show that it is extremely important to have a clear knowledge of the herbal complementary and alternative medicines used by Portuguese cancer patients and to assess healthcare professionals' familiarity and attitude towards its use by cancer patients.