An irrigation system for irrigation of a body cavity includes a reservoir, with an inlet for pouring liquid into the reservoir, an insertion member defining an insertion end for insertion into a body cavity through a body opening of a human being, the insertion member defining at least one opening, and a liquid tube fluidly connecting the reservoir with the insertion member. The reservoir has front and rear walls formed of a flexible, non-elastic polymer material, with the walls having edges sealed together. The reservoir has an upper liquid chamber and a lower liquid chamber, with the two chambers being separated by a first one-way valve.
