Interstitial fluid is a clear, colorless liquid that fills the spaces between cells in tissues. It serves as a medium for the exchange of nutrients, waste products, and gases between blood and cells. This fluid is essential for maintaining a stable environment for cells, allowing them to function properly. The composition of interstitial fluid is similar to that of blood plasma but contains fewer proteins. It is part of the extracellular fluid compartment, which also includes plasma and lymph. Proper balance of interstitial fluid is crucial for overall health, as imbalances can lead to conditions like edema.