Cladodes are the modified stems that fulfil the purpose that the leaves usually would do in other plants. Cladodes may be covered with large spines or small hair-like thorns (glochids). These short, sharp glochids cover the cactus and grow from the areoles, which are the places where flowers and thus fruit can develop. The cladodes contain carbohydrates (64–71 g/100 g DM), ash (19–23 g/100 g DM), fibre (18 g/100 g DM), protein (4–10 g/100 g DM) and lipids (1–4 g/100 g DM). 

They contain calcium, magnesium, potassium, phosphorus and trace amounts of iron. Younger cladodes contain higher carbohydrate, protein and water contents. The juice from cladodes is typically slightly acidic (pH 4.6) and therefore tastes sour. The high calcium and fibre content give cladodes a higher nutritional value than lettuce, but lower than spinach. Cladodes are classified as a low-calorie food.