Unlike what is widely anticipated by the public, herbal medicines are not always safe despite being
natural. We describe a 65-year-old Chinese man taking a prolonged maintenance dose of warfarin who
experienced an elevated international normalized ratio (INR) with associated bleeding after drinking
Gouqizi (goji berry) wine. This report illustrates that large doses (more than 6–12 g) of Gouqizi can significantly
enhance the anticoagulant action of warfarin and may cause similar adverse effects in keeping
with three previous reports. Therefore, the use of herbal medicines must adhere to pharmacopoeiarecommended
guidelines, including dosage regimes. Doctors should advise patients regarding possible
interactions between herbs and warfarin when prescribing and should increase the frequency ofINRmonitoring
for those patients concurrently receiving warfarin and medicinal herbs. Further study is needed
to do for the mechanism of interaction between Gouqizi and warfarin