When should you seek medical help for diarrhea? Most mild cases resolve within a few days with fluids and rest. Seek care immediately if diarrhea lasts more than three days, occurs in infants or older adults, or is accompanied by fever, severe abdominal pain, dehydration, blood, or black stools. Persistent vomiting, weight loss, or recent travel also warrant evaluation. People with chronic illness, weakened immunity, or recent antibiotic exposure should consult a clinician sooner. Do not self-prescribe antibiotics; treatments vary, and agents like cephalexin capsules wholesale are unrelated to routine diarrhea care unless specifically directed by a qualified healthcare professional.