Introduction of hysteroscopy to gynaecological daily practice caused huge progress in diagnostics and therapy of intrauterine pathology. The next phase was introducing the electroresectoscope and methods of permanent flow of drugs expanding the uterine cavity. To ensure optimal conditions for patient treatment and also economic reasons such procedures should be carried out in ambulatory mode or "one day surgery". It is necessary in that case to choose adequate anaesthesiological techniques, for example analgosedation. Analgosedation is an alternative to general anaesthesia. A major problem for the anaesthesiologist is keeping the correct level of analgosedation. Mostly to measure depth of sedation different scales are in use, for example Ramsay's scale. Application of bispectral analysis (BIS) to measure analgosedation in hysteroscopic procedures allows treatment to be carried out in the best comfort for the patient and in the most secure way, owing to dose optimisation of drugs used to obtain the correct level of analgosedation.