A client who experiences migraine headaches reports having fewer headaches since using the herbal remedy feverfew. Which information is most important for the nurse to include in a teaching plan for this client?

Feverfew may interact with aspirin or nonsteroidal antiinflammatory drugs (NSAIDs).

Those with allergies to chamomile, ragweed, or yarrow should not take feverfew.

Abdominal pain, gas, nausea, vomiting, and diarrhea can occur when taking feverfew.

Increased anxiety and nervousness have been reported by those taking feverfew.