Glucose-galactose malabsorption is a rare genetic disorder that affects the intestines' ability to absorb two simple sugars: glucose and galactose. This condition is caused by a deficiency in a specific transporter protein, leading to gastrointestinal symptoms such as diarrhea, bloating, and abdominal pain when these sugars are consumed. Individuals with this disorder must avoid foods containing glucose and galactose, including common items like milk and certain fruits. Diagnosis typically involves tests to measure sugar absorption, and management focuses on dietary modifications to prevent symptoms and ensure proper nutrition.