Left-side flank pain and diarrhoea

Diarrhoea can cause cramping and fluid loss, while bowel irritation may make pain feel spread across the abdomen or side. Flank pain with burning urine, frequent urination, fever, or chills points toward a urinary problem such as a Kidney Infection or Urinary Tract Infection rather than diarrhoea alone. Kidney Stones may cause severe side pain and nausea, although diarrhoea is not their defining feature. Recent food, travel, sick contacts, antibiotics, and the presence of blood or mucus in stool are useful clues.

Take frequent small sips of fluid; oral rehydration solution may help replace water and salts during ongoing diarrhoea. Choose light foods as tolerated and wash hands carefully. Avoid anti-diarrhoeal medicines if you have blood in stool or fever unless a clinician advises them. Seek review if symptoms persist, recur, or prevent normal drinking, or if flank pain is separate from bowel cramps.

Get urgent medical help for severe or worsening pain, a swollen or rigid abdomen, repeated vomiting, faintness, confusion, very little urine, blood in stool or urine, or fever with flank pain. Children, older adults, pregnant people, and people with kidney disease can become dehydrated quickly and should seek advice early.

Ask whether you need urine or stool testing, how to replace fluids safely, and which medicines to avoid. Share the diarrhoea duration, stool appearance, urine symptoms, fever, recent travel, food exposures, and antibiotic use.