No appetite, diarrhoea and fatigue

An intestinal infection can reduce appetite and cause diarrhoea, while loss of fluid and salts can leave you tired. Other possibilities include coeliac disease, anaemia, COVID-19, kidney disease, alcohol-related illness, burnout or chronic fatigue syndrome. These conditions have different patterns and treatments, so the combination alone cannot establish a cause. Note whether symptoms are sudden or longstanding and whether stools contain blood or mucus.

Drink regularly, using oral rehydration fluid when diarrhoea is frequent or you feel washed out. Eat small portions of familiar foods as tolerated rather than skipping intake for long periods. Rest, wash hands after using the toilet and avoid preparing food for others while diarrhoea continues. Keep track of stool frequency, urine, fever, pain, food triggers, recent travel, antibiotics and any weight change. Do not start supplements or anti-diarrhoeal medicines without checking they fit your symptoms.

Seek urgent help for blood or black stool, severe abdominal pain, fainting, confusion, severe weakness, very little urine or inability to drink. Arrange an appointment if diarrhoea persists, repeatedly returns, wakes you at night, or is accompanied by ongoing fatigue, fever, mouth ulcers or unplanned weight loss. People with kidney disease, diabetes, pregnancy or reduced immunity should seek advice sooner.

Ask whether you need stool or blood tests, how to replace fluids safely, and whether medicines or food intolerance could contribute. Tell the clinician about your usual bowel pattern, recent infections, travel, diet and alcohol intake.