Ozone medical applications gather strength, day by day. Ozone, in its oxidant status, administered in low doses and in a number of controlled treatments, is able to trigger the endogenous antioxidant systems achieving a redox balance.As such, it is able to control chronic oxidative stress associated with many diseases. Moreover, levels of nitric oxide and pro-inflammatory cytokines, like tumor necrosis factor (TNF-ɑ) and interleukin 1 and 6, were able to be modulated by ozone. Also, mitochondrial integrity and functionality was preserved, calcium homeostasis was achieved, adenosine A1 receptors were activated and activity of the superoxide dismutase enzyme was regulated [1]. In this lecture, preclinical and clinical studies of recent researches developed in Cuba are presented.Two topics have been selected: Alcoholism [2,3] and arthritis [4,5].In today's world, alcoholism is a serious health and social problem, affecting millions of people, without distinction of race, sex, culture or latitude. One diagnostic criterion of alcohol dependence is the appearance of a withdrawal syndrome when alcohol consumption ceases. Experimental studies have demonstrated that many consequences of withdrawal found in animals resemble those observed in humans. Such signs and symptoms of ethanol withdrawal (EW) include enhanced activity of the autonomic nervous system; body posture and motor abnormalities; hyperexcitability of the central nervous system (CNS), including sensory hyperreactivity, convulsion, anxiety, etc. Chronic ingestion of high levels of alcohol may bring about oxidative stress, associated with hepatic alterations, and of CNS, mainly due to the formation, through alcohol metabolism, of free radicals, acetaldehyde, lipid and protein oxidation and their reaction products.The protective effects of ozone on brain injury induced by oxidative stress and behavioral changes in rats, after 2 weeks of EW, were studied [2]. Also, a clinical trial with 10 alcoholic patients (elapsed time after ethanol withdrawal: ≤ 3 weeks) treated with ozone by rectal insufflation (ozone concentration from 20 to 35 mg/L and volumes from 100 to 150 ml) was performed [3]. In the preclinical study [2], 4 groups of rats (n=10 each one) were settled: I-Control, II-Ethanol, III-Ethanol + Ozone (20 mg/L, dose of 1 mg/kg, 10 sessions by rectal insufflation) and IV-Ethanol + Oxygen. At the end of EW, rats were subjected to behavioral tests followed by brain tissue collection to measure markers of oxidative damage. Ozone increased food consumption, maintained water intake at the same levels as the control group and reestablished cellular redox status. Anxiety, locomotor activity and memory/learning of the rats were improved. Ozone protected the brain against oxidative injury, improving important functions of the CNS. In the clinical study [3], the results demonstrated that ozone improved 70% of the signs from Clinical Institute Withdrawal Scale (CIWA-Ar), mainly those associated to CNS. Ozone efficacy was observed in patients that required