We evaluated various clinical and laboratory manifestations of toxic shock syndrome (TSS) in 17 menstruating females to define the spectrum of illness. Ten women had definite TSS, while seven who satisfied modified case definition criteria had probable TSS. Patients with definite TSS were younger, and symptoms developed later after onset of menstruation than in those with probable TSS. Overall, 16 (94%) had a rash with subsequent desquamation; 15 (88%), myalgias and orthostatic dizziness; 11 (79%), temperature of 38.9 degrees C or higher; 13 (76%), vomiting; 11 (65%), diarrhea; and 7 (54%), hypotension. All patients survived, and acute respiratory or oliguric renal failure possibly related to the absence of shock did not develop in any of them. None had a recurrent episode of TSS after treatment with an antistaphylococcal antibiotic, discontinuing tampon use, or both. Early recognition and treatment of less severely ill women may obviate potentially serious or fatal recurrences of TSS.