Abstract: Saliva samples are collected for body fluid constituent analysis by placing a sponge member into a patient's oral cavity. The sponge member is formed similarly to a pacifier nipple. Saliva is absorbed. The saliva is then expelled from the sponge member into a pipette. A filter may be placed between the sponge member and the pipette, through which the saliva is cleaned and molecular weight-selectively prepared by letting only substances through with a molecular weight below a cut-off weight. The integral unit is dismembered after the saliva has been transferred into the collection pipette, and the latter is tightly closed off for further handling.