A sanitizing protector for drainage pipes typically found below a sink, tub and other plumbing fixtures. The protector includes a housing with two connecting tubular ends. A tubular member is coaxially disposed within the housing and mounted at one end to one of the connecting ends. An annular channel is mounted to the internal surface of the cylindrical wall of the housing and the tubular member passes through without being in contact with it. A dispenser pump supplies an anti-bacterial, and optionally including a fragrance, liquid through a conduit that passes through the cylindrical wall to discharge the liquid in the annular channel. As the liquid reaches the rim of the annular channel, it spills over running downwardly along the internal surfaces of the cylindrical wall and pipe, sanitizing them and preventing any growth to proceed upwardly beyond the annular channel. The tubular ends may include an internal thread or they may be pressure-fitted in series with the drain pipes of the plumbing installation being protected.