A memory wipe is a medical procedure designed for the purpose of selectively eliminating memory engrams from the mind of an individual.
Dr. Katherine Pulaski developed a memory wipe technique which was effective on many humanoid species. It was used on Sarjenka, a young girl from the pre-warp civilization on Drema IV, in order to prevent her from telling her people of her experiences with the Enterprise. (TNG: "Pen Pals") The technique was not successful on all humanoids, however. Mintakans were unaffected by the memory wipe (TNG: "Who Watches The Watchers"), as were the Boraalans (TNG: "Homeward").