CF interferes with electrolyte and fluid balances in the body. In most CF patients, sweat is up to five times saltier than normal. Losing excess sodium and chloride can affect the heart rhythm and may sometimes cause shock.

In patients with CF, lubricating mucus in the lungs becomes thick and sticky, providing a breeding ground for microorganisms, causing frequent respiratory infections. These must be aggressively treated with intravenous, oral, and/or inhaled antibiotics. Much of the morbidity associated with CF is due to respiratory infections and lung complications.

Mucus plugs in the pancreas lead to blocked ducts, resulting in malabsorption because pancreatic enzymes are prevented from traveling to the intestine to digest proteins and fats. This can lead to vitamin deficiencies and malnutrition. Oral pancreatic enzyme supplements and replacement of fat-soluble vitamins A, D, E and K can ease these symptoms, along with a low fat, high protein diet. If pancreatic damage is sufficient, some CF patients eventually become diabetic.

Problems and symptoms associated with CF include: 

• Chronic cough and sputum production
• Persistent chest infection
• Meconium ileus (no stools in the first 24 to 48 hours of life) 
• Weight loss and malnutrition (failure to thrive) 
• Pancreatitis
• Chronic diarrhea and foul-smelling, greasy stools
• Diabetes related to chronic pancreatitis
• Delayed growth and delayed sexual development at puberty
• Enlargement or rounding (clubbing) of the fingertips and toes
• Chronic hepatic disease and biliary cirrhosis
• Hypoproteinemia and edema
• Rectal prolapse (protrusion of the rectum through the anus)
• Male infertility (obstructive azoospermia)