We present the legislation of the compulsory admission and treatment of mentally ill persons in the Swiss canton of Basle-City. We inquired retrospectively the requests of the clinic and the appointed time given by the psychiatric court of appeal in the year 2000. With 320 compulsory admissions there were 118 appeals. The patients with organic mental disorders are older and we exclude them for further examination because of the completely different psychosocial background. In the remaining 107 cases the schizophrenic disorders are clearly over-represented (75 % vs. 27 % of all admissions). Women are approx. 9 years older, are discharged three times more frequently at the negotiation and retained against their will for a shorter time than men. Men are more frequently isolated and compulsorily treated. The regression analysis can explain between 10 % and 16 % of the variance of the duration of the compulsory hospitalisation by the days of hospitalisation in the last two years and by sex.