Abstract: A method and an apparatus for reuse of anesthetics in inhalation anesthesia is described. In the method, fresh gas is mixed with highly concentrated anesthetic from an anesthetics evaporator (3) in a collector conduit (1) leading into and out of a patient, in such a way that, when the patient exhales, the exhalation gas is passed through an adsorption filter (5) disposed in the ingoing and outgoing collector conduit (1) and arranged distally relative to the outlet (4) from the anesthetics evaporator (3), as seen from the patient (2), the anesthetic not absorbed by the patient being adsorbed by an adsorption material (6) in the adsorption filter (5), while the rest of the exhalation gas leaves the apparatus, the adsorbed anesthetic being desorbed from the adsorption material (6) when the patient inhales and retransferred to the patient.