There is a link between gut and spondyloarthropathies, which extends from the acute ReA triggered by enteritis due to gram-negative bacteria to ankylosing spondylitis and peripheral arthritis in association with Crohn's disease and ulcerative colitis. In addition, in studies using ileocolonoscopy, an unexpectedly high proportion of patients with prolonged or chronic seronegative oligoarthritis or sacroiliitis have inflammatory changes in the terminal ileum or colon or both. These changes have either features of acute gut inflammation or infection, but about one quarter of the patients have chronic lesions, probably early Crohn's disease. The conventional treatment of spondyloarthropathies consists of liberal use of NSAIDs, local corticosteroid injections if indicated, and physiotherapy. In patients with acute ReA, the conventional antimicrobial therapy to eradicate the triggering infection is necessary if there is evidence of chlamydial or gonococcal etiology. This therapy does not, however, influence the course of the subsequent arthritis. Patients with chlamydia arthritis probably host living bacteria for prolonged periods, and they seem to benefit from a prolonged antimicrobial therapy with tetracyclines. In the face of frequent gut involvement in patients with prolonged or chronic spondyloarthropathies, the use of sulfasalazine is the logical alternative, as short-term studies on patients with ankylosing spondylitis indicate.