Mild traumatic brain injury is one of the most frequent pathologies seen in clinical practice. Patients are usually asymptomatic but sometimes present with minor symptoms. The symptoms may include organic complaints such as headaches and dizziness or more psychological ones such as anxiety or insomnia. When these symptoms continue for longer than a few weeks, we consider post-concussional syndrome. However, if no structural changes are evident in radiological images, it suggests subtle cellular changes, which alter the cerebral function and translate into a mental disturbance. Little is known about the mechanisms underlying this entity. The latest evidence regarding various biochemical and biomechanical changes involved in the development of post-concussional syndrome is taken in consideration. Different types of cellular death, cytoscheletal changes, and axonal transport dysfunction, among others, have been suggested to play a role. Most studies suggest the axonal dysfunction as being responsible for it.Finally, we discuss clinical aspects and the management of post-concussional syndrome as well as touching on predisposing factors. We revise the most common symptomatology, both organic and psychological. A usual approach to various symptoms is taken into account, however, the most effective treatment is the passing of time. In fact, most studies show that being asymptomatic after 1 year is the norm.