A wide variety of conditions have been mistaken for child abuse at one time or another, but congenital variants, disorders of the skin, bone fragility, and disorders of coagulation are the most common. Also, accidental injury is the most common differential diagnosis for non-accidental injury and presents significant diagnostic difficulty at times. A less common problem that has significance in certain localities involves injuries inflicted during cultural medical practices. In evaluating symptoms and conditions that may be confused with abuse, medical practitioners should use caution in determining the difference between reasonable and unreasonable explanations for observed trauma. When assessing histories of accidental injury, for example, health-care providers should distinguish between what is impossible and what is merely unlikely. When a medical history is developed, it should be thorough and consider all possible explanations for medical conditions. The time course of any marks on the body should be evaluated. A past history and review of symptoms may uncover additional clues to alternative medical diagnoses, such as phytodermatitis, contact allergy, diarrhea, and others. Family history may provide clues to hereditary conditions. Details of any accident should be obtained and apparent inconsistencies discussed. The child with bruising or bleeding should have a laboratory evaluation for disorders of coagulation. A relevant case vignette with follow-up questions is presented. 7 references