Analysis of literature data and own research showed an increase in the number of criminal and accidental acute poisonings with Tl compounds (Tl+) in all countries, in particular in Ukraine, which, including, is due to the availability of Tl+ on the Internet. Most often, these are group cases, often with fatal consequences or subsequent disability of patients, which is due to delayed diagnosis and late appointment of antidote therapy. It must be taken into account that in the conditions of war in Ukraine, the potential risk of using Tl+ for terrorist purposes is increased. Aim. Based on the analysis of the daily dynamics of the development of clinical manifestations, chemical-toxicological, biochemical, electroneuromyographic indicators and pathohistological data, improve the differential diagnosis of the main clinical syndromes in patients with acute oral and inhalation Tl+ compounds poisoning. Materials and Methods. A scientific analysis of literature data was carried out using reference databases of scientific libraries and own research on the daily increase of clinical, especially neurological symptoms specific for Tl+ poisoning against the background of gastrointestinal disorders. Clinical, laboratory, electroneuromyographic, toxicoanalytical and pathogistological research methods were used. Results. The daily sequence of the occurence and development of the main specific symptoms of acute Tl+ poisoning with low and high doses has been determined, which makes it possible to suspect poisoning in the first days and conduct a toxicological examination in a timely manner and prescribe antidote and detoxification therapy: in the first 2 days, the victims, against the background of gastrointestinal pathology, develop painful paresthesias not so much in the limbs, but in the oral cavity in case of oral poisoning and along the course of the upper respiratory tract, along with burning pains behind the sternum and a hoarse voice - in case of inhalation poisoning; on the 3rd-4th day before the appearance of alopecia, permanent paresthesias of the hair part of the head appear with the simultaneous appearance of focal pigmentation of the skin and darkening of the hair roots; in the first days of intoxication, intense burning symmetrical pains and paresthesias appear not only in the extremities, especially in the area of the feet, calf muscles, muscles of the inner surface of the thighs, shoulder girdle, chest, but also especially the scrotum in men and mammary glands in women. A comparison of clinical-toxicological and pathohistological indicators proved multi-organ damage to the body in case of poisoning with high doses of Tl+. Conclusions. The high toxicity of Tl+ compounds, the growth of criminal incidents, the potential risk of their use as terrorist purposes in the conditions of the war in Ukraine, determine the need for special control over the circulation of Tl+, blocking sites on the Internet that advertise the sale of highly toxic chemicals. The problem of ensuring the availability of a specific Ferrocin antidote in the pharmacy network, as well as the creation of an antidote reserve to eliminate the consequences of emergency situations, requires attention. Keywords: Tl compounds, acute criminal poisoning, sequence of symptoms, pathogistology.