In Japan, deaths in bathtubs or bathtub deaths are frequently investigated as unnatural deaths. About 19,000 bathtub deaths occur annually in Japan. This pattern of death has become a social issue in forensic pathology and emergency medicine and public health. It is assumed that the death of an adult by drowning in a bathtub cannot be avoided due to disturbance of consciousness. The PubMed database was used for literature search using the retrieval words, "bathing "OR" bathtub "AND" submersion "OR" drowning "OR" death "OR" cardiopulmonary arrest". From the epidemiological characteristics and pathophysiological findings of bath mortality in Japan, three etiologies of impaired consciousness have been proposed: acute ischemic heart failure, heatstroke, and blood pressure fluctuation. Moreover, other causes such as epilepsy and alcohol or drug intake cannot be ignored as potential risks for death in a bathtub. It is also important to note the possibility of suicide and, although extremely rare, homicide in a bathtub. Despite research, the exact causal relationship between bathtub bathing and death remains unclear. Further, the cause of death by postmortem investigation is not always easily determined. Hence, it is desirable to carry out a field survey of causes of death, including bathing conditions, and, wherever possible, a complete autopsy survey. An exclusion of critical cases such as crime-related death, suicide, drug poisoning, and carbon monoxide poisoning is optimal. Of the many hypotheses about the causes of bathtub mortality, the most consistent hypothesis will be medically inferred from the death history, case findings, and test results.
Keywords: bathtub; cardiopulmonary arrest; death; heat illness.