Abstract: An improved contraceptive diaphragm is provided which has a bioerodible matrix that disintegrates in the vaginal fluids within a predetermined period of time. The matrix is made from a water soluble gel, more particularly from a water soluble polymeric resin gel, and preferably from a polyvinyl alcohol resin gel. The solubility of the water soluble gel in the vaginal fluids is controllably reduced for example, by heat treatment of the gel after formation of the diaphragm. The diaphragm does not have to be removed in a single piece, but is excreted as a slight vaginal discharge. In one aspect of the invention, a natural collagenous protein is embedded in the matrix to assure sealing adherence of the diaphragm when positioned in the vagina. In another aspect of the invention a hydrophilic material is provided at the center of the matrix to effectively absorb secreted cervical mucus thereby creating a dry passageway which will impede entrance of the sperm.