The cytosol (also known as intracellular fluid (ICF) or cytoplasmic matrix, or groundplasm) is the internal fluid of the cell, and a part of cell metabolism occurs here.

Proteins within the cytosol play an important role in signal transduction pathways and glycolysis.

Cytosol mostly consists of water, dissolved ions, small molecules, and large water-soluble molecules (such as protein). It contains about 20% to 30% protein.

Normal human cytosolic pH is (roughly) 7.0 (i.e. neutral), whereas the pH of the extracellular fluid is 7.4.