Despite its past anonymity, senile dementia of the Alzheimer type is a disease with a major impact on our ageing society. It affects a considerable percentage of old and very old people (some 20% of people over the age of eighty), causing distress and discomfort for the sufferers and the carers; it causes close to 50% of all nursing home admissions and costs the nation probably more than $2 billion annually; it is, with cardiovascular diseases and cancer, a leading cause of death.One of the particular difficulties with senile dementia of the Alzheimer type (SDAT) is that the diagnosis only can be confirmed in the post‐mortem — during life the diagnosis can only be made with a limited degree of certainty by following established inclusion and exclusion criteria (Glen and Christie 1979); that is, by ruling out other known causes of dementia in a patient with a dementia syndrome it is concluded that it must be senile dementia of the Alzheimer type.One other interesting aspect is that in SDAT, a disease which I compared before with cancer and cardio‐vascular disease, a defeatist attitude amongst the medical profession is frequently noticed. Had the same attitude been adopted in the past towards cancer and cardio‐vascular disease, progress in diagnosis and treatment of these diseases would never have happened.I am suggesting that it is possible to adopt a less defeatist and more positive attitude towards SDAT and this then stimulates the development of working strategies and working hypotheses. A working hypothesis can never claim to be a final solution to the problem, it is merely a frame of thought that directs step by step research working towards piecemeal solution of the problem.SummaryA working hypothesis is presented, describing SDAT as a multi‐factorial condition, in which genetic factors, toxic factors and nutritional factors are interacting and may play an accelerating role in the development of SDAT.Depression, frequently co‐existing with SDAT, contributes to symptomatology and can be considered as playing an accelerating role.A tremendous amount of research has to be done.A working strategy at present could be:1. Increase research.2. Maintenance of a good nutritional status in the individual patient is mandatory. Nutritional research deserves high priority, based on early indications that secondary changes in nutritional condition may accelerate the process.3. More attention should be given, before the verdict of “Alzheimer” is pronounced, to the possibility that toxic factors have been contributing to the condition. Extra attention should be given to careful prescription of medication.4. Prevention, early recognition and vigorous treatment of depression seems to be a most important factor.The importance of psycho‐social stimulation should be recognised. The influence of the depression‐like state on the blood‐brain barrier function and on nutritional status of the brain should have high priori