Flavonoids may have some side effects depending on the dose, individual sensitivity, and interaction with other substances. Some of these side effects may include nausea, diarrhea, drowsiness, dry mouth, or low blood pressure. To avoid these side effects, it is advisable to start with low doses or consume flavonoids with food or water. It is also important to consult with a doctor before using them if you are taking any medications or supplements that may interact with them. Some examples of drugs that may interact with flavonoids are blood thinners (e.g., warfarin), anticoagulants (e.g., heparin), antiplatelets (e.g., aspirin), antidepressants (e.g., fluoxetine), anticonvulsants (e.g., phenytoin), antibiotics (e.g., ciprofloxacin), antifungals (e.g., ketoconazole), antihistamines (e.g., diphenhydramine), antihypertensives (e.g., lisinopril), anti-inflammatories (e.g., ibuprofen), antipsychotics (e.g., haloperidol), immunosuppressants (e.g., cyclosporine), opioids (e.g., morphine), sedatives (e.g., diazepam), or steroids (e.g., prednisone).