faeces Adults in Western societies excrete approximately 200 g of faeces each day. Faeces consist of unabsorbed water, undigested fibre, short chain fatty acids (which are a major product of fermentation), relatively low concentrations of salts, and an extremely large number of bacteria including anaerobes, lactobacilli, yeasts, and coliforms. Faeces are normally ‘formed’ rather than fluid; this is advantageous as it indicates effective retrieval of fluid and electrolytes, and is a component of the continence mechanism. The colour of faeces relates predominantly to the presence of bile ‘pigments; in obstructive jaundice, when bile pigments are unable to enter the intestine, the faeces become pale and sometimes almost white.

Faeces may change consistency in pathological states (see diarrhoea and constipation). Faeces become offensive in malabsorption states, particularly when increased quantities of fat enter the colon and are then available for bacterial degradation. This also results in increased quantities of gas being present in faeces, which accounts for the fact that faeces float when there is fat malabsorption. Faeces become hard and more difficult to pass when the diet is low in dietary fibre. Other conditions which result in slow intestinal transit also tend to produce hard faeces.

Faeces act as a vehicle for many intestinal infections when the organism can exist in its natural state or in the form of a cyst which enables the infective agent (usually a parasite) to exist outside its host in the environment. Careful disposal of faeces and clear separation between sewers and domestic water supplies has been one of the most important primary public health interventions to prevent the spread of infectious gastrointestinal diseases.

Michael Farthing, and Anne Ballinger

faeces Body waste, composed of undigested food residues, remains of digestive secretions that have not been reabsorbed, bacteria from the intestinal tract, cells, cell debris and mucus from the intestinal lining, and substances excreted into the intestinal tract (mainly in the bile). The average amount is about 100 g/day, but varies widely depending on the intake of dietary fibre.

faeces Waste material that is eliminated from the alimentary canal through the anus. Faeces consist of the indigestible residue of food that remains after the processes of digestion and absorption of nutrients and water have taken place, together with bacteria and dead cells shed from the gut lining.

faeces (feces) Waste material, consisting of the indigestible residues of food, bacteria, and dead cells from the lining of the alimentary canal, that is expelled from the body through the anus.

faeces (fee-seez) n. the waste material that is eliminated through the anus. It is formed in the colon and consists of a solid or semisolid mass of undigested food remains (chiefly cellulose) mixed with bile pigments (which are responsible for the colour), bacteria, various secretions (e.g. mucus), and some water.
—faecal (fee-kăl) adj.