Table 1.

Etiological Classification of Symptoms of IBS

IBS Subtype		Characteristics
IBS with diarrhea	IBS-D	Loose stools >25% of the time and hard stools <25% of the time Up to one-third of cases More common in men
IBS with constipation	IBS-C	Hard stools >25% of the time and loose stools <25% of the time Up to one-third of cases More common in women
Mixed or cycling	IBS IBS-M	Both hard and soft stools >25% of the time One-third to one-half of cases
Unsubtyped IBS		Insufficient abnormality of stool consistency to meet criteria

Abbreviation: IBS = irritable bowel syndrome.