Chemotherapy treatments in some neoplastic patients can result in unfavourable side-effects that can be accompanied by physical deterioration from changes in executive functioning, processing speed, and reaction times with a resulting inability to perform daily living activities (ADL) or a working disability from the loss of working memory and the inability to organise basic skills, affecting the quality of daily life. The literature has identified chemotherapy-induced cognitive impairment (CICI), also known as post-chemotherapy cognitive impairment (PCCI), chemobrain, or chemo-fog, since the late 1980s; nevertheless, the neurobiological causes of this illness are still not fully understood. According to the findings of the majority of studies done on patients with various neoplastic diseases, there is strong enough proof that certain drugs like doxorubicin, cyclophosphamide, cytarabine, methotrexate, 5-fluorouracil, and cisplatin play a significant part in the neurological impairment linked to chemo-fog. Therefore, it appears that the patients' physical incapacity is linked to the cytotoxic effects that chemotherapy medications have on the central nervous system, which may result in a temporary or permanent neurological impairment. Cognitive dysfunctions may affect a person's ability to make decisions for themselves by causing a temporary or recurring mental condition that may affect the preservation of their voluntary faculties and have an impact on the legal validity of any documents they sign. The fact that this pathological disease has non-negligible medico-legal ramifications since it affects areas of private law is what is driving the forensic medical community's rising interest in it.