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?

A. Abdominal pain, gas, nausea, vomiting, and diarrhea can occur when taking feverfew: Gastrointestinal upset is a common side effect of feverfew, so clients should be aware of these potential symptoms, but this is not the most critical teaching point. B. Increased anxiety and nervousness have been reported by those taking feverfew: There is limited evidence linking feverfew to increased anxiety or nervousness; this is not a primary concern or common adverse effect. C. Feverfew may interact with aspirin or nonsteroidal antiinflammatory drugs (NSAIDs): Feverfew can increase the risk of bleeding by potentiating the effects of aspirin and NSAIDs. Clients need to be cautioned about this interaction, especially if they take these medications regularly. D. Those with allergies to chamomile, ragweed, or yarrow should not take feverfew: Cross-reactivity is possible in clients allergic to these plants; however, counseling on bleeding risk when combined with other drugs takes precedence due to potential serious complications.