A nontreponemal spirochete was isolated from the rectum of a homosexual man with a chronic purulent discharge. Known infectious causes of the disease were excluded. Although the pathogenicity of the organism was not proved, the patient''s symptoms rapidly resolved following penicillin G benzathine therapy. When culture of a nonhemorrhagic, purulent rectal discharge fails to verify Neisseria gonorrhoeae, health care personnel are encouraged to carefully examine a Gram''s-stained smear of the discharge for spiral-shaped organisms.