In this review five older and lesser known clinical concepts which have weathered decades of clinical practice are presented along with the best supportive evidence that is currently available. Parenteral diarrhea is defined as diarrhea due to infections outside the gastrointestinal tract; and specifically, urinary tract infections are often associated with concomitant diarrhea. The otitis-conjunctivitis syndrome is a clinical observation that for specific infectious agents otitis media and conjunctivitis will commonly occur together. The concept of double-sickening; a potentially useful clinical presentation that commonly forecasts a secondary bacterial infection is also reviewed. Another lesser known topic discussed is the evidence that Candida species frequently colonize the skin in many diaper rashes and the early and more liberal administration of antifungal medications may be appropriate. Finally, in contrast to the common practice of aggressively treating fever, there is new and growing evidence suggesting that fever is actually beneficial to the patient. While these five older clinical concepts have variable degrees of supporting evidence, their longevity and usefulness over decades of clinical practice cannot be denied.