The present invention relates to cleansing of a suction line (1) of a dental care apparatus or of a suction line implemented as physically separately from a dental care apparatus, which suction line (1) includes means for producing a negative pressure and at least one suction hose (2). For the invention it is significant that in the suction line (1) a means has been arranged for enabling flow of the cleansing agent past a desired point and/or a means for enabling filling the line up to a desired point. The invention enables feeding cleansing agent to the suction line (1) in liquid form such that at least a part of the suction line (1) becomes filled with cleansing agent, which may be left standing in the suction line (1) or in a part of it for a desired time.
