faeces

Faeces are the solid or semisolid remains produced in the large intestine after digestion. In humans they consist mainly of water, but the dry matter includes bacteria, undigested dietary fibre, shed intestinal cells, mucus, bile pigments, salts, and minerals. The precise composition varies with diet, hydration, and gut health.

Faeces form as the colon absorbs water from the indigestible residue. Peristaltic movements move contents toward the rectum, where stool is excreted through the anus. Typical transit time from ingestion to defecation ranges from about 24 to 72 hours. Stool color is generally brown due to bile pigments; deviations can reflect dietary factors, medications, or health conditions. The Bristol Stool Scale is commonly used to describe stool consistency, ranging from hard lumps to entirely liquid.

Health status is often reflected in faeces. Normal patterns vary widely, but persistent changes in frequency, urgency, consistency, or presence of blood, mucus, or pale stools may indicate infections, inflammatory or irritable bowel disease, malabsorption, pancreatic or liver disorders, or colorectal conditions. Fecal tests can detect pathogens, inflammatory markers, blood, or parasites and are used in clinical diagnostics and public health screening.

Faeces host a diverse gut microbiota and play a role in digestion, nutrient synthesis, immune function, and protection against pathogens. They are also influenced by factors such as antibiotics, travel, and illness. In sanitation and agriculture, treated or processed faecal material (biosolids or manure) can be recycled as fertilizer under safety guidelines to minimize health risks. Proper hygiene and waste management are essential to prevent disease transmission.