A non-crosslinked, decellularized and purified mammalian tissue (e.g., bovine pericardium) having particular use as an implantable resorbable material. The material is treated by alkylating its primary amine groups in a manner sufficient to reduce the antigenicity of the tissue, permitting the treated tissue to be used in vivo and without crosslinking, and in turn, permitting it to be resorbable. The material can be used in surgical repair of soft tissue deficiencies for a certain period of time while the implant itself is gradually remodeled or absorbed by the host. Also provided are a method of preparing such a material, as well as a method of using such a material for surgical repair.
